Plate Design Research Articles

Improved breakdown voltage and dynamic Ron characteristics in normally-off GaN-based HEMTs featuring fully-recessed and bilayer-dielectric gate structure

Abstract The degradation of dynamic on-resistance (Ron) is a major challenge in GaN-based high electron mobility transistors (HEMTs), which seriously affects their performance and reliability. The degradation area of dynamic Ron mainly comes from two aspects. One is the region below the gate that also affects the threshold voltage (Vth) of the devices. And the other one is the interface region of the gate to drain access. The optimal device exhibits a Vth of 0.97 V, a small Vth hysteresis of only 20 mV, a high current density of 723 mA/mm, and a breakdown voltage (BV) of 760 V which could be further boosted when additional field plate design is employed. It is found that when high voltage drain stress is applied, a positive Vth shift is induced, leading to the decrease of the effective gate driving voltage, and thus the dynamic Ron of the devices is increased. Of particular concern is the effects of dielectric layer and/or interface of the access region on the dynamic Ron degradation, which can be alleviated by removing the dielectric layer of the access region.

A Universal Target Plate Design Scheme for Stellarators: theoretical basis and its application to heat load control

Abstract This study introduces a novel divertor target design scheme for stellarators, grounded in mathematical treatments and tailored to control toroidal heat load distributions. Initially, a differential equation characterizing toroidally uniform heat load distribution has been established in a two-dimensional (2D) slab configuration, and its analytic solution has been obtained. Subsequently, a numerical scheme has been developed to adapt the analytic solution into the 3D surface shape of stellarator target. The effectiveness of this design scheme has been validated through simulations of the Chinese First Quasi-axisymmetric Stellarator (CFQS) using a suite of codes including HINT, FLARE and EMC3-EIRENE, where a toroidally uniform heat load distribution has been achieved with an island configuration. Further, the effects of input parameters on the target shape and heat load distribution have been studied. The robustness of the designed target has been investigated by simulation results with varying magnetic island configurations, confirming that the toroidal uniformity of heat load distribution is insensitive to changes in island configurations. Moreover, the designed target has been assessed with gas puffing of neon, which shows that neon injections effectively reduce the heat loads without altering the toroidal uniformity of heat load distributions. The proposed scheme highlights the importance of theoretical and mathematical foundations of target design, offering an advantageous alternative/complement to the traditional numerical schemes.

Experimental and numerical investigations of liquid cooling plates for pouch lithium-ion batteries considering non-uniform heat generation

Ensuring the thermal safety of lithium-ion batteries requires efficient and reliable thermal management systems. However, the non-uniform heat generation of lithium-ion batteries results in uneven temperature distribution, which complicates the comprehension of the flow pattern design and operating parameter optimization in liquid-based battery thermal management, especially under extreme conditions. This study evaluates the thermal management performance of four classic liquid cooling plate designs for pouch batteries by considering their non-uniform heat generation through the electrochemical-thermal coupled model. Through experiment and numerical simulation, the optimal flow pattern is identified. Subsequently, the capability of the thermal management system, utilizing the best flow design, is further assessed under varying operating conditions. The results indicate that while a higher flow rate marginally enhances cooling, the coolant inlet temperature exerts a more substantial impact on the cooling performance. In addition, the recommended parameter settings for cell-level liquid cooling systems are outlined under extreme conditions. With a 5 C discharge rate and an initial temperature of 35 °C, the recommended coolant temperature range and coolant flow rate range are 20–30 °C and 60–100 mL min−1, respectively. As a typical example of computer-aided engineering, this study reveals the impact of battery non-uniform heat generation on battery temperature performance and provides a critical reference for the optimization of liquid-based battery thermal management systems.

Improving Liquid Desiccant Dehumidifiers through Square Baffle Plate Design and Nanofluid Innovation

Enhancing the performance of the liquid desiccant dehumidifier (LDDs) is pivotal, with mass transfer playing a significant role. Compared to the previous method, using a baffles plate improved liquid desiccant dehumidification performance. The study utilized an aqueous solution containing nanocarbon tubes (NCTs) in LiCl/H2O as the desiccant, cascading over baffles plate with a square profile. The performance of this system was determined using numerical methods. The concentrations of NCTs ranged from 0.03% to 0.5% by weight. Furthermore, this paper investigates the impact of nanoparticles and parameters, including flow rates, solution concentration, humidity, solution temperature, etc. on the analysis through Computational Fluid Dynamics (CFD) simulation. The study shows a 29% increase in moisture removal and humidity change, along with a 15.57% improvement in film thickness. These findings are underpinned by the principle of a reduced in contact angle from 57° to 29°, resulting in reduced partial pressure of water vapor from the solution, thereby enhancing the mass transfer mechanism. Consequently, the utilization of baffles plate demonstrates a significant improvement in the moisture removal performance of the LDDs.

Compact multi-ring perfect vortex beam generator fabricated by laser direct writing

Perfect vortex beams (PVBs) have received much attention in recent years since the annular intensity distributions are independent of the topological charge (TC). However, the cost-effective preparation of micrometer-scale monolithic devices capable of generating multiple PVBs through a simple approach remains a significant challenge. In this work, a design of double-ring perfect spiral phase plates (DPSPPs) is presented for the generation of PVBs at two distinct locations along the radial direction. The respective radii and spacing of the double-ring PVBs can be tuned by changing the control parameters. The proposed DPSPPs are fabricated by the flexible femtosecond laser direct writing (FsDLW) technique. The experimentally generated double-ring vortex beams with different TCs possess an almost constant radius, which is consistent with the characteristics of PVBs. Furthermore, the double-ring PVBs with different fractional and trigonometric function TCs and the multi-ring PVB are also demonstrated. The design and fabrication methods are expected to facilitate the miniaturization of the applications of PVBs in optical manipulation, optical communication, and high-capacity information storage.

Design and preparation of composite bipolar plates with synergistic conductive networks of graphite and metal foam

Graphite composite bipolar plate (BP) have limited conductivity, which makes them less than ideal for extensive application in proton exchange membrane fuel cell (PEMFC). In traditional graphite composite BP, the construction process of the conductive network is entirely random. To enhance conductivity, it is typically necessary to increase the content of conductive fillers or incorporate high aspect ratio carbon nanomaterials to optimize the density of the conductive network. In this work, we manufactured a highly conductive composite bipolar plate with synergistic conductive networks of graphite and metal foam (MF). With a synergistic conductive network, the ASR of CuG80-20ppi decreased to 7.7 mΩ cm2. Additionally, thermal conductivity increased to 24.76 W/(m·K), and in-plane conductivity reached 294.1 S/cm at 80 wt% mass fractions of conductive filler, using 20 ppi copper foam as the metallic conductive network. CuG80-20ppi exhibited a flexural strength of 52.2 MPa. G80 and CuG80-20ppi have the 80 wt% conductive filler and are molded into BP with parallel flow fields. CuG80-20ppi enhances the current density of PEMFC by 0.132 W/cm2 and reduces the ohmic impedance by 5.25%. Therefore, the findings of this study offer valuable insights for the enhancement of composite BP conductivity, while simultaneously ensuring the stability and continuity of the synergistic conductive network. A novel approach is presented to enhance the electrical conductivity of graphite composite bipolar plate (BP) for proton exchange membrane fuel cells (PEMFCs). By embedding metal foam as a supplementary conductive network within the graphite matrix, a synergistic conductive architecture is achieved. This innovation significantly reduces the area specific resistance (ASR) to 7.7 mΩ cm2 and boosts thermal conductivity to 24.76 W/(m·K). The resulting CuG80-20ppi BP, with 80 wt% conductive filler, exhibits improved mechanical strength and conductivity, contributing to a 0.132 W/cm2 increase in PEMFC current density and a 5.25% reduction in ohmic impedance. This work highlights the potential of metal foam integration to enhance BP conductivity and PEMFC performance.

Galerkin’s Method and Multivariate Newton’s Method for the Nonlinear Deformation of the Magneto-Electro-Elastic Bi-Layered Laminates

In this paper, mathematical modelling for the large deformation of a magneto-electro-elastic rectangular bi-layered laminate with general boundary conditions is presented. Constitutive equations involving the magneto-electro-elastic (MEE) material properties are introduced, Maxwell equations accounts for the electric and magnetic effects are also utilized. First-order shear deformation theory (FSDT) considering the von Karman nonlinear strain is adopted, and the plain strain/stress assumption applicable for thin plate analysis is used. A rather compact set of governing equations related to kinematical variables, electric/magnetic potentials and the Airy stress function is obtained as a consequence of the preliminary condensation for the electro-magnetic state to the plate kinematics. Semi-analytic solution for a bi-layered BaTiO3-CoFe2O4 laminate with specified boundary conditions subjected to various external applied loads is performed. By employing the Bubnov-Galerkin method, the set of nonlinear partial differential equations is transformed to a set of third-order nonlinear algebraic equations for the static deformation due to applied load. Numerical results are carried out by using the multivariate Newton's method with respect to various volume fractions indicating the volume ratio between piezoelectric BaTiO3 layer and piezomagnetic CoFe2O4. From the result, the nonlinearity of the von Karman strain appears to enhance system rigidity as smaller deformations will be detected when external load is applied. Also, some other interesting results are obtained which could be useful to future analysis and design of multiphase composite plates.

Angled Screws With Locking Plates-An Alternative Fixation for Minimally Invasive Mandibular Orthognathic Surgery.

The purpose of this study was to evaluate the short-term behavior of angled screws with locking plates after bilateral sagittal split osteotomy using the anterior oblique technique within the concept of minimally invasive orthognathic surgery (MIOS). Twenty patients who underwent bimaxillary surgery with mandibular advancement were included in this preliminary and retrospective study. All patients underwent computed tomography preoperatively and 1 day postoperatively. The incidence of neurosensory dysfunction, clinical evaluation of the occlusion and temporomandibular joint, and overall complications were recorded during a minimum follow-up of 4 months. The mean extent of sagittal mandibular advancement movements was 7.2mm (2.5-13.2mm). All patients had stable occlusion without evidence of temporomandibular joint dysfunction. None of the patients presented with dysaesthesia, hyperaesthesia, or anesthesia after four months of follow-up. The overall results of this study are very satisfactory with no major or minor complications. The new design of mandibular plates with locking screws can be an alternative in all orthognathic surgeries, but especially interesting for minimally invasive approaches where stronger fixation is needed. Long-term studies are needed to draw further conclusions.

Influence of Screw Angulation on the Mechanical Properties on a Polyaxial Locking Plate Fixation.

Polyaxial locking systems are widely used for strategic surgical placement, particularly in cases of osteoporotic bones, comminuted fractures, or when avoiding pre-existing prosthetics. However, studies suggest that polyaxiality negatively impacts system stiffness. We hypothesize that a new plate design, combining a narrow plate with asymmetric holes and polyaxial capabilities, could outperform narrow plates with symmetric holes. Three configurations were tested: Group 1 with six orthogonal screws, and Groups 2 and 3 with polyaxiality in the longitudinal and transverse axes, respectively. A biomechanical model assessed the bone/plate/screw interface under cyclic compression (5000 cycles) and torsion loads until failure. Screws were inserted up to 10° angle. None of the groups showed a significant loss of stiffness during compression (p > 0.05). Group 1 exhibited the highest initial stiffness, followed by Group 3 (<29%) and Group 2 (<35%). In torsional testing, Group 1 achieved the most load cycles (29.096 ± 1.342), while Groups 2 and 3 showed significantly fewer cycles to failure (6.657 ± 3.551 and 4.085 ± 1.934). These results confirm that polyaxiality, while beneficial for surgical placement, reduces biomechanical performance under torsion. Despite this, no group experienced complete decoupling of the screw-plate interface, indicating the robustness of the locking mechanism even under high stress.

Development Status of Flow Field Design for Bipolar Plates in Hydrogen Fuel Cells

This article provides a detailed introduction to the current development status of flow field design for hydrogen fuel cell bipolar plates, analyzes the impact of traditional and new flow field designs on fuel cell performance, and explores innovative designs such as biomimetic flow fields and three-dimensional flow fields through numerical simulation and experimental verification by domestic and foreign researchers. Some scholars have also studied the effect of adding protrusions, sub channels, or groove structures in the flow channel on improving the performance of fuel cells.This article provides the latest progress and recent research results in the flow field design of hydrogen fuel cell bipolar plates for future researchers. These contents have important reference value and guiding significance for researchers to further explore new flow field designs and improve flow field structures.

AI‐assisted Field Plate Design of GaN HEMT Device

AbstractGaN High Electron Mobility Transistors (HEMTs) plays a vital role in high‐power and high‐frequency electronics. Meeting the demanding performance requirements of these devices without compromising reliability is a challenging endeavor. Field Plates are employed to redistribute the electric field, minimizing the risk of device failure, especially in high‐voltage operations. While machine learning is applied to GaN device design, its application to field plate structures, known for their geometric complexity, is limited. This study introduces a novel approach to streamlining the field plate design process. It transforms complex 2D field plate structures into a concise feature space, reducing data requirements. A machine learning‐assisted design framework is proposed to optimize field plate structures and perform inverse design. This approach is not exclusive to the design of GaN HEMTs and can be extended to various semiconductor devices with field plate structures. The framework combines technology computer‐aided design (TCAD), machine learning, and optimization, streamlining the design process.

Three-Dimensional Changes of Alveolar Ridges and Nasolabial Structures Following a Digital Nasoalveolar Molding Therapy With a Novel Nasal Stent Activation Protocol

Digital orthodontics has been integrated into NasoAlveolar Molding (NAM) therapy to overcome challenges in the conventional NAM method. This study introduced an individualized Digital NAM (iDNAM) and evaluated the changes in the alveolar ridges and nasolabial morphology after iDNAM treatment. Prospective data were collected from 15 infants with complete unilateral cleft lip and palate who underwent iDNAM therapy. An intraoral-and-nasolabial scan was used to create a virtual setup model and plate generation. A total of 2 plates were required under the iDNAM treatment protocol. The first iDNAM plate has a specific interior and exterior design to allow continuous force application with minimal plate adjustment. After an intermediate scan, a nasal stent was meticulously incorporated into the second plate for nasal molding. To activate the nasal stent, a silicone molding extension was used instead of manually adding acrylic. The alveolar cleft gap was significantly reduced by 7.48 ± 2.06 mm. On the cleft side, statistically significant increases occurred in nostril height, columellar length, and nasal base–columellar angle (2.08 ± 0.63 mm, 2.58 ± 0.28 mm, and 22.29 ± 0.88 degrees, respectively). By using 2 serial plates, iDNAM improved the alveolar cleft gap and the nasal morphology in complete unilateral cleft lip and palate. An addition of a nasal extension to the second iDNAM plate presents a challenge as accurate positioning is required for appropriate activation force. The iDNAM plate design and nasal activation protocol reduce the need for chairside adjustment and the number of appointments.

Personalised High Tibial Osteotomy Surgery Is Accurate: An Assessment Using 3D Distance Mapping

Early-stage knee osteoarthritis is often suitable for treatment with high tibial osteotomy (HTO). This is an effective joint-preserving treatment, resulting in good postoperative outcomes. To overcome the limitations of traditional HTO, the surgical technique and correction accuracy can be enhanced by personalised procedures using three-dimensional digital planning and metal additive manufacturing, The purpose of this clinical trial study was to evaluate the three-dimensional accuracy of a new personalised HTO procedure, using modern imaging techniques, 3D modelling, and distance map analysis (DMA). Twenty-five patients were treated with the personalised HTO procedure. Before surgery and after 6 months, they underwent clinical evaluation scoring, radiographic imaging, and computed-tomography scanning to generate morphological models. Specifically, preoperative tibia models were used to plan the tibia correction and the design and position of the fixation plate. Preoperative, planned, and postoperative models were imported in computer-aided and designing software (Geomagic ControlTM 2014, 3D Systems, Rock Hill, SC, USA) for DMA implementation to assess geometrical differences between model surfaces. A very good reproduction of the planned tibia morphology was achieved postoperatively (average differences between −0.9 mm and 1.4 mm). DMA values associated with fixation-plate deformation were less than 1 mm, similar to those for plate-to-tibia surface-contour matching. Overall, personalised digitally planned HTO utilising three-dimensional printed surgical guides and plates enables accurate planned correction and plate placement.

Optimal design of vibration resistance of fiber-reinforced composite sandwich plates embedded in a viscoelastic square honeycomb core

This work focuses on investigating the optimal design of composite sandwich plates (FCSPs) with a viscoelastic square honeycomb core (VSHC). Firstly, using the cross-fill theory, the complex modulus technique, the first-order shear deformation theory, the minimum strain energy principle, and the Newmark-β method, a theoretical model of the VSHC-FCSPs under half-sine pulse excitation is formulated to calculate the inherent frequencies, the peak and vibration decay time of the transient response in time domain. The peak and vibration decay time are taken as the indexes of the anti-vibration performance. Considering an index of structural stiffness performance, the average value of the inherent frequencies is adopted to calculate the overall stiffness. After a set of literature validations and optimization validations, the multi-objective genetic algorithm is employed to study the optimization issue of VSHC-FCSPs. The optimization objectives are to minimize the three design variables of the transient response peak, vibration decay time, and reciprocal of overall stiffness. Then, the fiber laying angle of each layer, the core thickness ratio and the modulus ratio are assumed as optimization variables. Finally, the results with good vibration resistance and structural stiffness in the Pareto front are chosen as references, and these corresponding variations of the design variables and optimization objectives are obtained. The optimization results have revealed that the optimization variables corresponding to the intermediate points should be selected as references to improve the anti-vibration capacity and ensure the structural stiffness performance.

Design of true zero-order half-wave plates using KCsMoP2O9 crystal: A novel molybdophosphate material with extremely small birefringence

The true zero-order half-wave plates (HWPs) with millimeter thicknesses were manufactured using the KCsMoP2O9 (KCMP) crystal with extremely small birefringence (Δn = 0.007 at 1064 nm). The designed KCMP HWPs showed small sensibility (wavelength, temperature, and angle), wide operating waveband (50 nm at >200:1), good thermal stability (>900:1 at 80oC), high extinction ratio (>2500:1), and excellent phase-retardation characteristics. In addition, an optical attenuator assembly of KCMP HWP (A16M0) and polarizers was designed. The transmittance could be adjusted well from 0 to 1 by the designed optical attenuator, comparable to commercial quartz HWP (glued zero-order HWP). All results indicated that the KCMP crystal is a good candidate as a wave plate material with the potential for polarization modulation in optical systems.

A simple method and case study of task planning for collaborative design based on FDSM

In multiperson collaborative mechanical product design, unreasonable task allocation can result in excessive coupling between tasks, complex design communication, and rework, particularly in small enterprises and teams that rely primarily on experience. Hence, this study proposes a simple and efficient task-planning method based on a fuzzy design structure matrix (FDSM), which involves single-level task decomposition, three-level number assignment of the coupling relationship, decoupling of the structural tree algorithm, and validation of the optimization results based on the G-value. Design tasks are promptly allocated into a single level based on the functional structure module of the product. The task-correlation degree is quantified based on three levels of numerical values through personal experience to construct an FDSM, the latter of which is decoupled by the correlation degree of the structural tree algorithm to obtain the optimized sequence and allocation of the collaborative design task. Finally, the effectiveness of the planning is verified by calculating the tightness of the corresponding matrix before and after the planning. A task-planning case of a riveting-machine design for capacitor cover plates is established to validate this method.

Optimalisasi Desain Struktur Gedung Interdisciplinary Engineering (IDE) – Fakultas Teknik Universitas Indonesia dengan Memanfaatkan BIM (Building Information Modelling)

Project design is a step in the construction process that determines the technical requirements to be applied when the project is constructed. BIM (Building Information Modeling) is a form of technological innovation used in project design. BIM (Building Information Modeling) has become the main factor for increasing efficiency and accuracy; using BIM, everything related to design, construction, scheduling, and costs can be integrated into one digital platform that all stakeholders can access. In this paper, the structural planning optimization of the Interdisciplinary Engineering (IDE) Building - Faculty of Engineering, University of Indonesia, will be carried out. This building planning refers to (SNI-2847-2019) concerning Structural Concrete Requirements for Buildings and (SNI-1726-2019) concerning Procedures for Planning for Earthquake Resistance of Structures. Outputs are generated through superstructure and substructure plans, the design of foundation structures, columns, beams, and plates, 2D Detail Engineering Design (DED), 3D modeling, and construction management plans in the form of Budget Plans and scheduling.

Modeling the Effect of Cell Orientation on the Performance of an Air-Breathing Polymer Electrolyte Fuel Cell with a Columnar Cathode Plate

Air-breathing polymer electrolyte fuel cells (PEMFCs) are expected to play an important role in the development of sustainable portable and mobile devices, such as unnamed aerial vehicles, motorbikes or laptops. In this work, the performance of air-breathing PEMFCs with a columnar cathode plate design is examined by means of a 3D two-phase, non-isothermal model, and compared against experimental data. The results show that the performance is highly influenced by the cell orientation, namely horizontal (material plane perpendicular to gravity) versus vertical (material plane parallel to gravity). Oxygen transport in horizontal cells is mainly dominated by diffusion, leading to oxygen shortage toward the cell center and an inhomogeneous current density distribution. In contrast, oxygen transport in vertical cells is assisted by natural convection, enhancing oxygen transport throughout the cell and increasing the current density homogeneity. Water saturation is preferentially accumulated close to the cell center, being larger in horizontal cells due to the lower water removal rate of the cathode plate.

Modeling the Effect of Cell Orientation on the Performance of an Air-Breathing Polymer Electrolyte Fuel Cell with a Columnar Cathode Plate

Air-breathing polymer electrolyte fuel cells (PEMFCs) are expected to play an important role in the development of sustainable portable and mobile devices, such as unnamed aerial vehicles, motorbikes or laptops. In this work, the performance of air-breathing PEMFCs with a columnar cathode plate design is examined by means of a 3D two-phase, non-isothermal model, and compared against experimental data. The results show that the performance is highly influenced by the cell orientation, namely horizontal (material plane perpendicular to gravity) versus vertical (material plane parallel to gravity). Oxygen transport in horizontal cells is mainly dominated by diffusion, leading to oxygen shortage toward the cell center and an inhomogeneous current density distribution. In contrast, oxygen transport in vertical cells is assisted by natural convection, enhancing oxygen transport throughout the cell and increasing the current density homogeneity. Water saturation is preferentially accumulated close to the cell center, being larger in horizontal cells due to the lower water removal rate of the cathode plate.

Evaluation of Stability and Stress Distribution on Plate and Bone for Correction of Anterior Open Bite with Le Fort I Osteotomy: New Plate Design

Aim: Many different fixation methods have been proposed in the literature for the treatment of open bite. Beginning with the use of plates and screws, rigid fixation methods have become commonplace, however, open bite is a disorder prone to relapse despite rigid fixation. In our study, we aimed to eliminate the need for guided split usage during surgery and to increase postoperative stabilization in open bite patients with a new personalized plate design. Material and Method: For this purpose, a three-dimensional (3D) head model was created in the virtual environment. After the Le Fort I osteotomy on the model, the inferior segment of the maxilla was placed 1 cm forward and positioned to leave a space between the inferior and superior part of the maxilla. Different fixation methods were applied to fix the bone segments. In the first group, four plates with a thickness of 0.8 mm were fixed. In the other groups, we used three different thicknesses (0.4 mm, 0.6 mm, 0.8 mm) of the continuous plate we designed. The amount of movement and tension that occurred on the bone segments, plates, and screws were evaluated. Results: The maximum movement in the study was observed with the standard 4-plate fixation method, and the minimum movement was observed with the custom plate system with 11-screw type with a thickness of 0.8 mm. As a result, it has been found that the custom-made continuous plates provide a more rigid fixation than the standard plates. Conclusion: It may be possible to reduce the likelihood of a relapse problem by designing a plate with the appropriate thickness and form to spread the stress on the bone over a wider area.