Analysis and optimization of stamping and forming process of bearing outer ring

To address the common issues of wrinkling,tearing,and uneven wall thickness in the actual sheet metal stamp-ing process of the outer ring of needle roller bearings,this study analyzes critical technical indicators such asforming limits,thickness distribution,and principal strains in the forming process in detail.Three-dimensionalmodels of the concave and convex dies were constructed.The effects of different process parameters,includingstamping speed,edge pressure,sheet metal thickness,and friction coefficient,on the quality of the forming partswere investigated by varying these parameters.Subsequently,the orthogonal experimental method was used todetermine an optimal experimental group from multiple sets of experiments.It was found that under the processparameters of a stamping speed of 3000 mm/s,edge pressure of 2000 N,sheet metal thickness of 0.9 mm,andfriction coefficient of 0.125,the forming quality of the outer ring of the bearing is ideal.

A low-profile dual-polarization programmable dual-beam scanning antenna array

low-profile dual-polarization dual-beam scanning antenna array based on holographic control theory is presented in this paper.The radiating elements are ingeniously designed to achieve reconfigurable polarization and modulation of the radiation phase by controlling the state of the PIN diodes integrated on each element.A 72-channel series-parallel equal-amplitude and in-phase feeding network is integrated with the radiating array to achieve low-profile characteristics.The two-dimensional(2D)dynamic and accurate deflection of the beam is achieved by a designed direct current(DC)bias circuit that digitally encodes the antenna array using the single-chip microcontroller.A 2-element subarray and a 6x12 array have been fabricated and the digitally controllable radiation pattern of this antenna system has been experimentally verified.The antenna system can achieve the beam scanning of-30°to 30°with a step-scan of 5°at 11 GHz.

GaN-based LEDs for light communication

Rapid improvement in the efficiency of GaN-based LEDs not only speed up its applications for general illumination, but offer the possibilities for data transmission. This review is to provide an overview of current progresses of GaN-based LEDs for light communications. The modulation bandwidth of GaN-based LEDs has been first improved by optimizing the LED epilayer structures and the modulation bandwidth of 73 MHz was achieved at the driving current density of 40 A/cm2 by changing the multi-quantum well structures. After that, in order to increase the current density tolerance, different parallel flip-chip micro-LED arrays were fabricated. With a high injected current density of ~7900 A/cm2, a maximum modulation bandwidth of ~227 MHz was obtained with optical power greater than 30 mW. Besides the increase of carrier concentrations, the radiative recombination coefficient B was also enhanced by modifying the photon surrounding environment based on some novel nanostructures such as resonant cavity, surface plasmon, and photonic crystals. The optical 3 dB modulation bandwidth of GaN-based nanostructure LEDs with Ag nanoparticles was enhanced by 2 times compared with GaN-based nanostructure LEDs without Ag nanoparticles.Our results demonstrate that using the QW-SP coupling can effectively help to enhance the carrier spontaneous emission rate and also increase the modulation bandwidth for LEDs, especially for LEDs with high intrinsic IQE. In addition, we discuss the progress of the faster color conversion stimulated by GaN-based LEDs.

Blockchain-driven supply chain finance solution for small and medium enterprises

Blockchain has attracted much attention in recent years with the development of cryptocurrency and digital assets.As the underlying technology of cryptocurrency,blockchain has numerous benefits,such as decentralization,collective maintenance,tamper-resistance,traceability,and anonymity.The potential of the blockchain technology(BT)is widely recognized in the financial field.Although some scholars have proposed the combination of blockchain and supply chain finance(SCF),the details of this combination is rarely mentioned.This study first analyzes the coupling between SCF and blockchain technology.Second,the conceptual framework of blockchain-driven SCF platform(BcSCFP)is presented.Third,the operation process of three SCF models on the BcSCFP is proposed.Finally,a case study combined with actual events is conducted.This paper has a positive practical significance in the operation and management of banks and loan enterprises.