Construction of A Personalized Service Model of ABC Community Fresh E-commerce Based on Small Data

The homogenization of products and services in the development of community fresh e-commerce is more serious, and providing personalized services to community customers has become a new development key point. From the perspective of small data research, this paper proposes an e-commerce service model that uses small data to provide personalized fresh products for community customers. Taking ABC community convenience store as the research object, the paper analyzes the application of community customer small data in the personalized service of community fresh convenience store to improve the loyalty and satisfaction of community customers and promote the development of community fresh e-commerce

Novel magnetic topological insulator FeBi2_2Te4_4 with controllable topological quantum phase

Here, we report a new intrinsic magnetic topological insulator FeBi$_2$Te$_4$ based on first-principles calculations and it can achieve a rich topological phase under pressure modulation. Without pressure, we predict that both FeBi$_2$Te$_4$ ferromagnetic and antiferromagnetic orders are non-trivial topological insulators. Furthermore, FeBi$_2$Te$_4$ of FM-z order will undergo a series of phase transitions from topological insulator to semimetals and then to trivial insulator under pressure. Finally, we further clarify and verify topological phase transitions with low-energy effective model calculations. This topological phase transition process is attributed to the synergy of the magnetic moment and the spin-orbit coupling. The unique topological properties of FeBi$_2$Te$_4$ will be of great interest in driving the development of quantum effects

Structural Transformations in Ferroelectrics Discovered by Raman Spectroscopy

Ferroelectrics systems are of great interest from the fundamental as well as applications points, such as ferroelectric random access memories, electro-optic switches and a number of electro-optic devices. Curie temperature (TC) is one of the important parameters of ferroelectrics for high-temperature applications. Particularly, the optical modes, which are associated with the ferroelectric to paraelectric phase transition, are of great interest. Structural transformations that alter the crystal symmetry often have a significant effect on the Raman spectroscopy. This chapter systematically studies the type ferroelectric oxides and rare earth element doped ferroelectric materials such as PbTiO3-Bi(Mg0.5Ti0.5)O3 (PT-BMT), Sr x Ba1−x Nb2O6 (SBN), Pb1−1.5x La x Zr0.42Sn0.4Ti0.18O3 (PLZST), Bi1−xLaxFe1−yTiyO3 (BLFT) and (K0.5Na0.5)NbO3-0.05LiNbO3 (KNN-LN) and so on synthesis of single crystal/ceramic and optical phonon vibration modes and the improvement of the Curie temperature characteristic using spectrometry measurements. The TC, distortion degree, and phase structure of the ferroelectric materials have been investigated by temperature-dependent Raman spectroscopy. Meanwhile, the important physical parameters exhibited a strong dependence on dopants resulting in structural modifications and performance promotion

XRD Characterization of Phenol Liquefied Chinese Fir Residues

The amount of wood residue is used as a measurement of the extent of wood liquefaction. Characterization of the residue from wood liquefaction provides a new approach to understand some fundamental aspects of the liquefaction reaction. This paper adopts X-ray diffraction to characterize the changes of groups and mechanism of reaction of the residue crystallinity in the liquefaction process of Chinese Fir. The XRD analysis of liquefaction residue showed that amorphous region is firstly damaged so that the crystallinity could be in the trend of increasing in the liquefaction process of Chinese fir in most cases with the time’s prolonging. However, cellulose crystalline region begins to be destroyed under the higher liquefied temperature (170℃）or in the case of higher P/W (w/w) ratio (5), leading to the relative decreased trend of crystallinity. Key words: Chinese Fir; XRD; Liquefaction; Residu

Topological Phases, Local Magnetic Moments, and Spin Polarization Triggered by C558-Line Defects in Graphene

We study the electronic properties of a novel topological defect structure for graphene interspersed with C558-line defects along the Armchair boundary. This system has the topological property of being topologically three-periodic and the type-II Dirac-fermionic character of the embedded topological phase. At the same time, we show computationally that the topological properties of the system are overly dependent on the coupling of this line defect. Using strain engineering to regulate the magnitude of hopping at the defect, the position of the energy level can be easily changed to achieve a topological phase transition. We also discuss the local magnetic moment and the ferromagnetic ground state in the context of line defects, which is the conclusion after considering additional Coulomb interactions. This leads to spin polarization of the whole system. Finally, by modulating the local magnetic moment at the position of the line defect, we achieve a tunable spin quantum conductance in a one-dimensional nanoribbon. Near the Fermi energy level, it also has the property of complete spin polarization. Consequently, spin filtering can be achieved by varying the incident energy of the electrons.Comment: 8 pages, 6 figure