Search

We developed a triazatruxene-based hole transport material (HTM), 3Ka-DBT-3Ka, aiming to enhance band alignment and augment charge generation and collection in devices, as an alternative for 1,2-ethanedithiol (EDT). The PbS CQD solar cells employing 3Ka-DBT-3Ka as the HTM achieve a peak efficiency of 11.4%, surpassing devices employing the conventional PbS-EDT HTM (8.9%). [ABSTRACT FROM AUTHOR]

The rotor attitude detection of spherical motors usually requires the installation of position sensors on the rotor shaft or stator to achieve, which occupy a large space and cause negative effects for the practical installation and application of spherical motors. In this paper, a sensorless position detection method for reluctance spherical motors based on the structure and operating characteristics of reluctance spherical motors is proposed. By detecting the stator coil inductance data at different rotor attitude angles, the position prediction model is constructed using the extreme learning machine algorithm. Through comparison and validation, it is demonstrated that the rotor attitude angle obtained by the method is highly accurate, providing a feasible idea for the control and application of reluctance spherical motors. [ABSTRACT FROM AUTHOR]

This article proposes a rotor attitude estimation (RAE) method for spherical motors using the multiobject Kalman kernel correlation filter (MKKCF) algorithm in monocular vision. A permanent magnet spherical motor (PMSpM) is adopted as the research object, and a monocular area scan camera is equipped in the RAE system with a visual feature component mounted on top of the rotor output shaft. In the proposed MKKCF algorithm, the Kalman filter is used to enhance the robustness and accuracy of KCF tracker for each object. To simplify the proposed algorithm verification, a one-object tracking comparison is conducted among the KCF algorithm, the fast discriminative scale space tracking (FDSST) algorithm, and the Kalman KCF algorithm, and the results show that Kalman KCF tracker is more applicable for RAE. In addition, an RAE test bench is developed, and the MKKCF-based RAE method and the micro-electro-mechanical system (MEMS) (MPU9250) method are compared when estimating the rotor attitude. To set a benchmark, the contact rotor position measurement with encoders is used. The comparison results indicate that the MKKCF-based RAE method works with higher accuracy than the MEMS method. Finally, a closed-loop PMSpM control experiment is conducted by using the proposed MKKCF-based RAE method, and the practicability of the proposed method is proved. [ABSTRACT FROM AUTHOR]

A permanent magnet spherical motor (PMSpM) is a representative multiple degree-of-freedom electric apparatus. This paper proposes new analytical models for the PMSpM with stepped cylindrical permanent magnets (PMs). The research is not only to obtain the magnetic field and torque models of the PMSpM but also to yield a potential analytic tool for the spatial magnetic field and torque decomposition. The model decomposition aims to acquire a potential tool for the future research on PMSpM topology optimization and working mechanism. To achieve the two research targets above, the toroidal expansion method is used for magnetic field modeling, and the finite element method verification and experimental verification are conducted. Then, forces and torques are deduced from the Lorentz force law. In addition, a prototype PMSpM has been produced and the comparison studies of the air-gap flux density and torque among decomposed components are conducted using finite element analysis results and experimental results. It is concluded that the proposed analytical PMSpM models and the model decomposition method are proved. [ABSTRACT FROM AUTHOR]

• Graphitic N-pyridinic N-thiophene S synergistic active sites were constructed in HSNGS. • HSNGS exhibited the highest efficiency to degrade TC in practical water with TOF of 6.24 min−1. • Continuous and fast removal of TC in practical water was achieved. • Thiophene S coordinated metal ions in practical water, leading to a synergistic enhancement of the degradation performance and stability. The rational design of active sites in nanocarbons are the long-term pursuit for their practical applications. However, N, as the most potential active site, still encounters the problems of low atom utilization efficiency and stability in practical environmental remediation. Herein, we successfully constructed synergistic active sites consisting of graphitic N, pyridinic N, and thiophene S in heavy S, N co-doped hollow graphene spheres (HSNGS). The HSNGS exhibited exceptional efficiency in degrading tetracycline in real water, with a turnover frequency of 6.24 min−1, which is among the highest reported. Moreover, tetracycline dissolved in practical water could be continuously and rapidly eliminated by passing through a column filled with HSNGS, maintaining its high performance even after 40 consecutive cycles. In the synergistic active sites, graphitic N and pyridinic N species accepted electrons from peroxymonosulfate, generating singlet oxygen for tetracycline degradation. Simultaneously, thiophene S coordinated with metal ions present in the practical water, synergistically enhancing the degradation of tetracycline. Additionally, the coordinated metal ions provided protection for the synergistic active sites during peroxymonosulfate activation, preventing their oxidation and enabling the continuous and rapid degradation of tetracycline. This work opens up possibilities for the industrial application of nanocarbon materials in environmental remediation. [ABSTRACT FROM AUTHOR]

This paper proposes a monolayer Halbach array based permanent magnet spherical motor (PMSpM) using cubic permanent magnets (PM). The research aims to provide a fast computing model to calculate the magnetic field for this PMSpM, which helps for future PMSpM optimization and control study. Three thickness equivalence principles are provided and compared for cubic PMs. The magnetic scalar potential is introduced, and the spherical harmonics expansion is implemented for rotor magnetic field analysis. Engineering revision is used to reduce the Legendre function deviation in polar angle direction. Torques and forces are deduced using the Lorentz force law, and relatively simple models of this PMSpM for both magnetic fields and torques are acquired. In addition, a prototype motor has been developed, and the analytic results of air-gap flux density and torque are compared with their finite element simulation and experimental results, which are proved consistent. It is concluded that the fundamental component of the spherical harmonics can be used to present the magnetic field model, which uses fewer integrals than the Biot-Savart law based solution, and the modeling results of the magnetic field flux density, forces and torques are in line with the expectations. The analytic models are proved correct. [ABSTRACT FROM AUTHOR]

A spherical motor has multiple degrees of freedom. Its motion control requires an accurate attitude detection system. This study proposes a low‐cost microelectromechanical system (MEMS) inertial measurement sensor to detect the attitude of the spherical motor. The proposed sensor combines a three‐axis gyroscope and a three‐axis accelerometer to obtain raw position data of spherical motors to estimate rotor's attitude. To improve the accuracy of the estimated attitude from the raw position data, the authors reduce the inclination angle error between the motor's rotor and MEMS sensor's coordinate systems by compensating axial angle error. A high‐speed camera that generally provides high accuracy of the attitude is used as a calibration device for comparison and validation. Experimental results show that the MEMS inertial measurement sensor can achieve accurate attitude estimation that is suitable for motion control of a spherical motor. [ABSTRACT FROM AUTHOR]