K-doped Ba122 epitaxial thin film on MgO substrate by buffer engineering

Molecular beam epitaxy of K-doped Ba122 (Ba$_{1-x}$K$_x$Fe$_\text{2}$As$_\text{2}$) superconductor was realized on a MgO substrate. Microstructural observation revealed that the undoped Ba122 served as a perfect buffer layer for epitaxial growth of the K-doped Ba122. The film exhibited a high critical temperature of 39.8 K and a high critical current density of 3.9 MA/cm$^\text{2}$ at 4 K. The successful growth of epitaxial thin film will enable artificial single grain boundary on oxide bicrystal substrates and reveal the grain boundary transport nature of K-doped Ba122.Comment: 5 pages, 4 figures, accepted manuscript Supercond. Sci. Technol 202

Nanoscale Texture and Microstructure in a NdFeAs(O,F)/IBAD-MgO Superconducting Thin Film with Superior Critical Current Properties

This paper reports the nanoscale texture and microstructure of a high-performance NdFeAs(O,F) superconducting thin film grown by molecular beam epitaxy on a textured MgO/Y2O3/Hastelloy substrate. The NdFeAs(O,F) film forms a highly textured columnar grain structure by epitaxial growth on the MgO template. Although the film contains stacking faults along the ab-plane as well as grain boundaries perpendicular to the ab-plane, good superconducting properties are measured: a critical temperature, T-c, of 46 K and a self-field critical current density, J(c), of 2 x 10(6) A/cm(2) at 4.2 K. Automated crystal orientation mapping by scanning precession electron diffraction in transmission electron microscope is employed to analyze the misorientation angles between adjacent grains in a large ensemble (247 grains), and 99% of the grain boundaries show in-plane misorientation angles (Delta gamma) less than the critical angle theta(c), which satisfies one of the necessary conditions for the high J(c). Comparing the columnar grain size distribution with the mean distance of the flux line lattice, the triple junctions of low-angle grain boundaries are found to be effective pinning centers, even at high temperatures (>= 35 K) and/or low magnetic fields

The contribution and interactive relationship of tourism industry development and technological innovation to the informatization level: Based on the context of low-carbon development

Research background: Informatization is a new economic form arising from a new round of technological and industrial changes. Information technology has been used to promote the integrated development of the tourism industry and propel technological innovation, which will help accelerate the achievement of the strategic goals of carbon emission peaking and carbon neutrality. China’s informatization level has improved to a certain extent due to the concentration of capital and technological innovation brought about by the government-led model, and also owing to the consumer dynamics released by the industry-side reform.Research contents and methods: This study constructs a panel vector auto-regression model to investigate the impact of tourism industry development and technological innovation on informatization based on Chinese provincial statistics from 2010 to 2019. This study adopts the entropy method, Monte Carlo simulation, variance decomposition, and pulse response to investigate the impact, characteristics, and trends of their interactions.Results: First, tourism industry development, technological innovation, and informatization all experience inertia development and have self-reinforcing mechanisms during the research period. Second, tourism industry development and technological innovation have a significantly positive impact on the enhancement of informatization, and their influence presents a trend, from upward to downward. Third, tourism industry development has a positive impact on technological innovation, and the response trend presents a curve approximately inverted U-shape. Fourth, from the results of variance decomposition, the contribution of technological innovation to the improvement of informatization level increases rapidly and reaches 18.5% and then levels off. The contribution rate of tourism industry development to the improvement of informatization level gradually rises and reaches 5.1%, finally tending to be stable.Contribution: This study reveals that tourism industry development and technological innovation will exert different pulling effects on informatization at different development stages in China and their advantages and provides theoretical contributions to tourism industry development and technological innovation on the advancement of informatization level. The research results provide a reference basis for the government and related industrial sectors in how to effectively facilitate the development of informatization in the context of the low-carbon economy

Encoding Enhanced Complex CNN for Accurate and Highly Accelerated MRI

Magnetic resonance imaging (MRI) using hyperpolarized noble gases provides a way to visualize the structure and function of human lung, but the long imaging time limits its broad research and clinical applications. Deep learning has demonstrated great potential for accelerating MRI by reconstructing images from undersampled data. However, most existing deep conventional neural networks (CNN) directly apply square convolution to k-space data without considering the inherent properties of k-space sampling, limiting k-space learning efficiency and image reconstruction quality. In this work, we propose an encoding enhanced (EN2) complex CNN for highly undersampled pulmonary MRI reconstruction. EN2 employs convolution along either the frequency or phase-encoding direction, resembling the mechanisms of k-space sampling, to maximize the utilization of the encoding correlation and integrity within a row or column of k-space. We also employ complex convolution to learn rich representations from the complex k-space data. In addition, we develop a feature-strengthened modularized unit to further boost the reconstruction performance. Experiments demonstrate that our approach can accurately reconstruct hyperpolarized 129Xe and 1H lung MRI from 6-fold undersampled k-space data and provide lung function measurements with minimal biases compared with fully-sampled image. These results demonstrate the effectiveness of the proposed algorithmic components and indicate that the proposed approach could be used for accelerated pulmonary MRI in research and clinical lung disease patient care

Research and Exploration of Artificial Intelligence in Product Design in the Era of Intelligent Interconnection

In the era of intelligent interconnection, artificial intelligence has brought tremendous technological changes to people's production and life. Including smart home, smart city, intelligent design, and artificial intelligence has been applied to all areas of our life, its application in the field of product design and creation is more and more extensive. Through the analysis of the concept of artificial intelligence, combined with the development of artificial intelligence and product design tools driven by new technological revolution such as Internet of Things, big data and artificial intelligence, this paper determines the value of artificial intelligence in product design and development, and explores the application strategy and future development prospect of artificial intelligence in product design process. Through the creative integration of artificial intelligence and product design, it can not only bring innovative means and paradigms for product design, but also bring more choices and possibilities for designers and users. However, AI cannot completely replace human product design and creation. Artificial intelligence will be the focus of product design development in the new era, and some empirical applications of artificial intelligence in product design are given. Analyzing the application of AI in product design in the era of intelligent interconnection can help us better understand the real demand and development direction of artificial intelligence

Renormalization group analysis of ultracold Fermi gases with two-body attractive interaction

We propose a new functional renormalization group (RG) strategy to investigate the many-body physics of interacting ultracold Fermi gases. By mapping the Ginzburg-Landau (GL) action of Fermi gases onto a complex φ4-model, we can obtain the closed flow equation in the one-loop approximation. An analysis of the emerging RG flow gives the ground state behavior. The Hamiltonian of a Fermi gas with a two-body attractive interaction is used as a demonstration to clarify our treatment. The fixed point structure reveals not only the condensation phase transition, but also the Bardeen-Cooper-Schrieffer (BCS) to Bose-Einstein condensation (BEC) crossover. The effect of the imaginary time renormalization is also discussed. It is shown that for the dynamical field configuration our RG procedure can reproduce the well known theoretical results of BCS-BEC crossover, while under a static approximation the phase transition takes place at a higher critical temperature

Spin chirality driven by the Dzyaloshinskii–Moriya interaction in one-dimensional antiferromagnetic chain

Dzyaloshinskii–Moriya (DM) interactions cause many interesting physical features, such as topologically nontrivial magnetic skyrmions and chiral domain walls. These interactions become more pronounced in low-dimensional systems. We investigated a one-dimensional Heisenberg spin-1/2 chain with an asymmetric DM interaction. The results show that, upon applying a nonzero DM interaction, the Néel ground state transitions to a spin chiral phase. Moreover, using the mean-field approximation, we obtain the dispersion of the energy spectrum, from which the z-axis spin chirality is calculated as a function of the strength of the DM interaction for low-lying excitations. The results indicate that the DM interaction facilitates chirality for Dz ≤ J and induces a spin-gapped chiral state