Tailoring Interfacial Exchange Anisotropy in Hard–Soft Core-Shell Ferrite Nanoparticles for Magnetic Hyperthermia Applications

Magnetically hard–soft core-shell ferrite nanoparticles are synthesized using an organometallic decomposition method through seed-mediated growth. Two sets of core-shell nanoparticles (S1 and S2) with different shell (Fe3O4) thicknesses and similar core (CoFe2O4) sizes are obtained by varying the initial quantities of seed nanoparticles of size 6.0 ± 1.0 nm. The nanoparticles synthesized have average sizes of 9.5 ± 1.1 (S1) and 12.2 ± 1.7 (S2) nm with corresponding shell thicknesses of 3.5 and 6.1 nm. Magnetic properties are investigated under field-cooled and zero-field-cooled conditions at several temperatures and field cooling values. Magnetic heating efficiency for magnetic hyperthermia applications is investigated by measuring the specific absorption rate (SAR) in alternating magnetic fields at several field strengths and frequencies. The exchange bias is found to have a nonmonotonic and oscillatory relationship with temperature at all fields. SAR values of both core-shell samples are found to be considerably larger than that of the single-phase bare core particles. The effective anisotropy and SAR values are found to be larger in S2 than those in S1. However, the saturation magnetization displays the opposite behavior. These results are attributed to the occurrence of spin-glass regions at the core-shell interface of different amounts in the two samples. The novel outcome is that the interfacial exchange anisotropy of core-shell nanoparticles can be tailored to produce large effective magnetic anisotropy and thus large SAR values.

Hyperchaos in a Bose-Hubbard Chain with Rydberg-Dressed Interactions

We study the chaos and hyperchaos of Rydberg-dressed Bose–Einstein condensates (BECs) in a one-dimensional optical lattice. Due to the long-range, soft-core interaction between the dressed atoms, the dynamics of the BECs are described by the extended Bose-Hubbard model. In the mean-field regime, we analyze the dynamical stability of the BEC by focusing on the ground state and localized state configurations. Lyapunov exponents of the two configurations are calculated by varying the soft-core interaction strength, potential bias, and length of the lattice. Both configurations can have multiple positive Lyapunov exponents, exhibiting hyperchaotic dynamics. We show the dependence of the number of the positive Lyapunov exponents and the largest Lyapunov exponent on the length of the optical lattice. The largest Lyapunov exponent is directly proportional to areas of phase space encompassed by the associated Poincaré sections. We demonstrate that linear and hysteresis quenches of the lattice potential and the dressed interaction lead to distinct dynamics due to the chaos and hyperchaos. Our work is relevant to current research on chaos as well as collective and emergent nonlinear dynamics of BECs with long-range interactions.

Study of a Multi-Fusion Positioning System Based on Beidou Indoor Inertial Navigation

This article proposes an indoor combined positioning terminal based on Beidou pseudofiles and micro-inertial navigation sensors. Through the built-in Beidou pseudo lite positioning IP soft core, it can receive and analyse Beidou satellite signals. The article creates BDS ground inertial positioning data receiving hardware; performs inertial positioning data primary information identification authentication on the inertial data received by the hardware; performs multi-inertial data fusion estimation calculation on inertial positioning data after authentication, reduces the dimensional error value, and completes the proposed system Design. The program makes full use of the data resources of the existing airborne equipment, does not need to transmit radio signals, and the user capacity is not limited, which is suitable for highly dynamic users. Through simulation and sports car test, it is proved that the scheme is feasible.

A Design Method for Low-cost and SOPC-based Flexible Lifting Control System

To efficiently reduce the development and production costs of the intelligent lifting control system, we introduce a design method for the intelligent lifting system with client-server architecture. We replace DSP processor core or DSP (Digital Signal processor) core with Nois II soft-core processor so that the design and production costs can be effectively cut. By replacing DSP processor or DSP processor core with Nois II soft-core processor, the design and production costs can be significantly reduced. In our design, loop vector control units work as a server processor, and a central computing unit with four independent multipliers and two adders is employed, with the implementation method based on a state machine. The experimental results prove effective in reducing resource requirements for FPGA (Field Programmable Gate Array), show that the proposed method can be successfully applied to the implementation of a complete intelligent flexible lifting control system on a low-end Altera Cyclone FPGA, and servo motor control achieves better dynamic performance