99 research outputs found
Analysis and Design of a Bidirectional Isolated DC-DC Converter for Fuel Cell and Super-Capacitor Hybrid System
Planar Integrated Magnetics (PIM) Module in Hybrid Bidirectional DC-DC Converter for Fuel Cell Application
Analysis of Planar E+I and ER+I Transformers for Low-Voltage High-Current DC/DC Converters with Focus on Winding Losses and Leakage Inductance
Efficiency Optimization by Considering the High Voltage Flyback Transformer Parasitics using an Automatic Winding Layout Technique
Leakage Inductance Calculation for Planar Transformers with a Magnetic Shunt
The magnetic shunt is generally inserted in a planar transformer to increase the leakage inductance, which can be utilized as the series inductor in resonant circuits such as the LLC resonant converter. This paper presents a calculation methodology for the leakage inductance of the transformer with a magnetic shunt by means of the stored magnetic energy in the primary and secondary sides of the transformer using the magnetomotive force (MMF) variation method, as well as the stored energy in the shunt based on the reluctance model. The detailed calculation method is described. Both the finite-element analysis simulation and the experimental results have proven the validity of the proposed calculation method for leakage inductance
Planar integrated magnetics design in wide input range DC-DC converter for fuel cell application
Volcanically-induced floral changes across the Triassic-Jurassic (T-J) transition
The End-Triassic Mass Extinction (ETME) saw the catastrophic loss of ca. 50% of marine genera temporally associated with emplacement of the Central Atlantic Magmatic Province (CAMP). However, the effects of the ETME on land is a controversial topic. Evaluation of the disparate cause(s) and effects of the extinction requires additional, detailed terrestrial records of these events. Here, we present a multidisciplinary record of volcanism and environmental change from an expanded Triassic-Jurassic (T-J) transition preserved in lacustrine sediments from the Jiyuan Basin, North China. High-resolution chemostratigraphy, palynological, kerogen, and sedimentological data reveal that terrestrial conditions responded to and were defined by large-scale volcanism. The record of sedimentary mercury reveals two discrete CAMP eruptive phases during the T-J transition. Each of these can be correlated with large, negative C isotope excursions (CIE-I of -4.7 â°; CIE-II of -2.9 â°), significantly reduced plant diversity (with ca. 45% and 44% generic losses respectively), enhanced wildfire (marked by increased fusinite or charcoal content), and major climatic shifts towards drier and hotter conditions (indicated by the occurrence of calcareous nodules, increased Classopollis pollen content, and PCA analysis). Our results show that CAMP eruptions may have followed a bimodal eruptive model and demonstrate the powerful ability of large-scale volcanism to alter the global C cycle and profoundly affect the climate, in turn leading to enhanced wildfires and a collapse in land plant diversity during the T-J transition
Making 2âD Materials Mechanochemically by TwinâScrew Extrusion:Continuous Exfoliation of Graphite to MultiâLayered Graphene
Mechanochemistry has developed rapidly in recent years for efficient chemicals and materials synthesis. Twin screw extrusion (TSE) is a particularly promising technique in this regard because of its continuous and scalable nature. A key aspect of TSE is that it provides high shear and mixing. Because of the high shear, it potentially also offers a way to delaminate 2âD materials. Indeed, the synthesis of 2âD materials in a scalable and continuous manor remains a challenge in their industrialization. Here, as a proofâofâprinciple, the automated, continuous mechanochemical exfoliation of graphite to give multiâlayer graphene (MLG, â6 layers) by TSE is demonstrated. To achieve this, a solidâandâliquidâassisted extrusion (SLAE) process is developed in which organic additives such as pyrene are rendered liquid due to the high temperatures used, to assist with the exfoliation, and simultaneously solid sodium chloride is used as a grinding aid. This gave MLG in high yield (25 wt%) with a short residence time (8 min) and notably with negligible evidence for structural deterioration (defects or oxidation)
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