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The fluid kinematics of Liutex decomposes a velocity gradient tensor (VGT) of ∇vinto four components, including rotation (R), stretching/compressing (SC), anti-symmetric shear (Santi-sym) and symmetric shear (Ssym), as oppose to the traditional Cauchy-Stokes decomposition where a VGT was decomposed into the strain rate and vorticity tensors. The current study limpidly clarified the physical meanings of these deformations in the newly-proposed decomposition from the perspectives of both fluid kinematics and dynamics. With in-depth understanding the physical connotations of these deformations, the present study further suggests that the Ssymbe the only deformation appropriately correlated to the stress tensor, leading to the establishment of a new constitutive relation for Newtonian fluids with the modified model assumptions originated from Stokes in 1845. Moreover, the present research finds that the “principal decomposition” proposed by Liu is not mathematically unique when a VGT has three real eigenvalues (TR). Within the context, a new decomposition method is introduced to avoid the non-uniqueness issue arising from using the principal decomposition to establish fluid dynamics equations. Based on the modified Stokes assumptions and the novel VGT decomposition method, a set of new fluid dynamics momentum equations are obtained for Newtonian fluid. The added stress tensor of Faddis identified as the key difference between the newly-derived governing equations and the conventional Navier-Stokes (N-S) equations, which is caused by excluding the SCcorrelation to the stress tensor in the new constitutive equation. Finally, a preliminary analysis of Faddis conducted using the existing channel turbulence direct numerical simulations (DNS) data based on the traditional N-S equations. The Faddis found widely existing in turbulence and is of the same order of magnitude with the other force terms. Therefore, the Faddis expected to have some nonnegligible effects on altering the current DNS data based on the traditional N-S equations, which will be further verified by performing the “DNS” simulation using the newly-derived fluid dynamics equations in near future.

Faced with the global climate change, as a major greenhouse gas emitter, China launched a pilot policy on low-carbon city construction since 2010. Few studies have discussed how climate policies affect the investment and financing behavior of energy-intensive enterprises. Based on the micro data of A-share listed enterprises in China’s energy-intensive industries, this study aims to assess the productivity effect of low-carbon city pilot (LCCP) policy and investigates the mechanism of financing and investment using the difference-in-difference method. Empirical results provide evidence that the LCCP policy has significantly improved the total factor productivity of energy-intensive enterprises. In terms of the mechanisms, the LCCP policy has increased the supply of bank credit to enterprises and encouraged their long-term investment in fixed assets and R&D activities. The productivity effect of the LCCP policy is greater for state-owned enterprises and enterprises with political connection. Urban human capital, industrial agglomeration, and resource endowment contribute to the productivity effect of LCCP policy for enterprises in the energy-intensive industries. The findings show that the LCCP is an effective comprehensive policy to promote the high-quality development of energy-intensive industries, and the findings also provide enlightenment for enacting better climate transition policies.

Conducting polymer nanocoatings render plastics to possess interesting optical, chemical, and electrical properties. It nevertheless remains technically challenging to deposit uniform conducting polymer nanocoatings on ambient plastic substrates ascribed to the inert and varied chemical properties of plastics and the notorious processability of conducting polymers. Previous studies have made progress in delivering various conducting polymer thin films viaoxidative chemical vapor deposition. Herein, we develop a solution-based approach to polyaniline (PANI) and PEGylated PANI nanocoatings on multiple engineering plastics followed by evaluating their antifouling performance. The procedure relies on the formation of uniform, lyotropic V2O5·nH2O thin films on plastics assisted by a surfactant—sodium N-lauroylsarcosinate. Next, in situ, oxidative polymerization causes the formation of nanofibrous PANI nanocoatings. Finally, interfacial functionalization leads to PEGylated PANI nanocoatings, and the steric nanolayer effectively repels the adsorption of bovine serum albumin and the attachment of the bacterium Pseudoalteromonassp. on the surface. It is worth noting that the antifouling properties rely mainly on the presence of PEGylated PANI nanocoatings, irrespective of the type of plastic substrates underneath. The current study therefore opens an avenue for the solution-based delivery of conducting polymer-based, functional nanocoatings on hydrophobic substrates in a controllable manner with the availability of further modification.

In this paper, a novel triple-band dipole antenna is presented. The proposed antenna has a very simple structure and is easily designed. The idea of the antenna is based on the traditional wideband bow-tie dipole antenna. Via etching slots on the bow-tie patch, three bent dipoles with different lengths which correspond to different operating frequencies are formed. Hence, the triple-band antenna is generated. Each operating frequency band realizes wideband and can be adjusted almost independently. And the antenna is fed by a 50 Ω microstrip line and a wideband microtrip-to-coplanar-stripline (CPS) transition as a balun. The good performances of the proposed antenna are achieved by a mass of simulations and measurements. The measured results have a good agreement with the simulated ones. The results show that the proposed antenna obtains three bandwidths at 2.38~2.65 GHz (10.7 %), 3.17~4.08 GHz (25.1 %), and 4.75~6.00 GHz (23.2 %) with the reflection coefficient less than −10 dB. In addition, the stable gain and quasi-omnidirectional radiation patterns are obtained in the operating frequency bands. Therefore, the proposed antenna is suitable for WLAN/WiMAX/LTE applications.

A simple ultra-wideband magneto-electric dipole antenna utilizing a differential-fed structure is designed. The antenna mainly comprises three parts, including a novel circular horned reflector, two vertical semicircular shorted patches as a magnetic dipole, and a horizontal U-shaped semicircular electric dipole. A differential feeding structure working as a perfect balun excites the designed antenna. The results of simulation have a good match with the ones of measurement. Results indicate that the designed antenna achieves a wide frequency bandwidth of 107 % which is 3.19~10.61 GHz, when VSWR is below 2. Via introducing the circular horned reflector, the designed antenna attains a steady and high gain of 12±1.5dBi. Moreover, settled broadside direction main beam, high front-to-back ratio, low cross polarization, and the symmetrical and relatively stable radiation patterns in the E-and H-plane are gotten in the impedance bandwidth range. In the practical applications, the proposed antenna that is dc grounded and has a simple structure satisfies the requirement of many outdoor antennas.

This paper presents a new algorithm for the three‐dimensional marine controlled source electromagnetic method modeling in arbitrarily anisotropic medium based on unstructured grids and coulomb gauge. In order to avoid the effect of source singularity, we apply the secondary potential formulation for the quasi‐static of Maxwell's equation. Next, solving the finite element equations with IDR(s) iterative algorithm method combined with the incomplete LU decomposition technology. Once the secondary vector and scalar potential is solved, we can use the moving least square method to calculate their spatial derivative and compute the secondary electric and magnetic field. In order to test the finite element method for numerical modeling of 3D controlled source electromagnetic data in an arbitrarily anisotropic conductive medium of this paper, we applied the developed algorithm to compute the typical CSEM response of two 3D models. The modeling results show that the proposed algorithm is feasible and effective; the IDR(s) is competitive with or superior to ILU‐QMR, ILU‐BICGSTAB methods; the proposed algorithm is general and can be applied to EM modeling in borehole and environment geophysics in arbitrarily anisotropic medium.

In this work, a new forging process is proposed for bottom instead of the original casting process. In order to achieve better technological parameters combination, the finite element method (FEM) and orthogonal experiment were utilized to research the process of cylinder bottom forging. Forming maximum load, mould maximum wear and forging maximum damage were chosen as evaluating indicators. Billet preheating temperature, the mold preheating temperature, forging speed and friction factor were taken into consideration to analysis the influence on forming quality for the bottom. The significant factors and the optimal value, i.e. Billet preheating temperature (1150°C),the mold preheating temperature (350°C),the forging speed (50mm/s) and the friction factor (0.2) were determined. After the technological experiment, the qualified quality cylinder bottom can be manufactured by the optimized forging process.

Multiple-component Bose-Einstein condensation has been observed in a magnetic field generated by a controllable magnetic quadrupole-Ioffe-configuration trap. Different distributions of atoms in spinor Bose–Einstein condensates are created by changing the time difference of switching-off current in quadrupole-Ioffe-configuration coils and bias coils of the magnetic trap. A simple analysis is carried out to explain some phenomena of the experiment.

We study the decay behaviors of ultracold atoms in metastable states with spin-orbit coupling (SOC), and demonstrate that there are two SOC-induced decay mechanisms. One arises from the trapping potential and the other is due to interatomic collision. We present general schemes for calculating decay rates from these two mechanisms, and illustrate how the decay rates can be controlled by experimental parameters. We experimentally measure the decay rates over a broad parameter region, and the results agree well with theoretical calculations. This work provides an insight for both quantum simulation involving metastable dressed states and studies on few-body problems with SO coupling. [ABSTRACT FROM AUTHOR]