Current Issue : October-December Volume : 2025 Issue Number : 4 Articles : 5 Articles
Advanced manufacturing has been extensively studied using various resin monomers and customized apparatus. Multimaterial microfabrication tools remain limited due to the size constraints inherent in extrusion-based fabrication methods. In addition, prior research predominantly employs monomers as “inert” resins, with minimal emphasis on altering their properties during fabrication. In this study, we propose a novel approach to field-coupled advanced manufacturing, wherein external stimulative fields are integrated to dynamically modulate the properties of “dynamic” resins during 3D printing. As a demonstration, we utilize an electric field-coupled two-photon polymerization (EF-TPP) technique to fabricate structurally colorful microstructures. To address the challenges of limited fabrication approach and resins in the field of structural color, we present an EF-TPP system that enables the production of 3D structural colorful microstructures. By coupling the electric field with the two-photon polymerization (TPP) process, this method enhances 3D printing capabilities, allowing for the bottom-up fabrication of structural colorful microstructures. Furthermore, it integrates existing electrically tunable heliconical cholesteric liquid crystals, enabling the modulation of structural color during printing while also accelerating the printing speed. This approach facilitates the production of microstructures with multiple structural colors without requiring changes to the resin ink. By eliminating the lithography step, the EF-TPP system promotes green manufacturing practices and introduces an unconventional paradigm for fabricating dynamic, microscale structural colorful devices. Additionally, the electric field-integrated two-photon lithography system provides a foundational strategy for advancing field-coupled manufacturing methodologies....
The experimental and computational characterization of a cold model prototype designed to test the electromagnetic properties of a new RFQ (Radio-Frequency Quadrupole) cavity is reported. This cavity is intended to be an essential part of a compact, high-gradient proton accelerator for medical purposes. The RFQ’s design employs a novel RF power-coupler injection solution. One common way to couple the RF power in proton RFQs has been the use of loop-couplers inserted into the mid-section of the RFQ’s lobe sections. This technique has been demonstrated to be reliable and effective but introduces a significant perturbation into the lobe that can be more noticeable when dealing with compact structures. We propose a RF injection scheme that uses direct transition from a coaxial cable to the RFQ by connecting the inner coaxial conductor to the RFQ vane body. As a consequence, the lobe geometry is not perturbed, and the transversal electrical fields are directly excited through the vanes. Moreover, by using a pair of such couplers connected to opposite vanes at a given transversal plane of the RFQ, it is also possible to excite the desired quadrupolar TE210 modes while avoiding the excitation of dipolar TE110 modes. The resonances corresponding to different RFQ modes have been characterized, and the dependence of the amplitude of the modes on the relative phase of the field injected through the RF power ports has been demonstrated both by measurements and simulations....
In three-phase three-post insulators, air gaps and crack defects are important sources of partial discharge and surface flashover. Using finite element analysis software, this study created a three-dimensional simulation model to investigate the effect of these defects on electric field distribution. The effects of crack defects and air gaps of different sizes and locations on the electric field distribution were then methodically investigated. According to the results, the most significant electric field distortion is caused by air gap defects close to the phase A conductor, and the distortion is exacerbated by shorter air gap lengths. Air gap length has much less effect on the electric field in the phase B conductor. There is no obvious change in electric field strength with the radius of air gap defects (0.1–2 mm). The electric field strength is negatively correlated with crack height; greater height reduces distortion, while crack width and depth are positively correlated with the surrounding field strength; greater dimensions increase distortion....
Cr alloyed Cu exhibits puzzlingly high electrical conductivity compared with other 3d elements alloying. Here, we present a theoretical understanding based on standard electronic band structure calculations. The inuence of local spin-polarization on electrical conductivity was rst investigated. It is found that the non-magnetic calculation produces a high density of states peak at the Fermi level, and then it fails to explain the high electrical conductivity of Cu-Cr alloy. When spin polarization is taken into account, the density of states is signicantly reduced, and the results are in good agreement with experimental measurements. Meanwhile, the calculation results can explain the increase in strength and also lead to some interesting deductions. Finally, a computational program is proposed to select a high electrical conductivity Cu alloy based on a simple calculation model....
Adjustable-speed drives (ASD) are extensively adopted in industrial power systems due to their ability to enhance overall efficiency by supplying optimal power to motors based on specific speed and torque requirements. While much existing research focuses on conventional diode rectifiers or voltage-source inverters as front-end solutions, this paper introduces a three-phase power factor correction (PFC) approach using a common DC-link voltage for motor drive applications. This innovative method significantly reduces input current harmonics and improves power factor with minimal active switching components and straightforward control strategies. Furthermore, the DC-link bus can be utilized for multiple motor drives as well. Both analytical and simulation studies validate the effectiveness of the proposed system, demonstrating that the input currents achieve a sine wave form with a unity power factor, while total harmonic distortion of the input current (THDi) is minimized to approximately 2% at the rated power level....
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