Patterned catalyst layer boosts the performance of proton exchange membrane fuel cells by optimizing water management

Mass transport is crucial to the performance of proton exchange membrane fuel cells,especially at high current densities.Generally,the oxygen and the generated water share same transmission medium but move towards opposite direction,which leads to serious mass transfer problems.Herein,a series of patterned catalyst layer were prepared with a simple one-step impressing method using nylon sieves as templates.With grooves 100μm in width and 8μm in depth on the surface of cathode catalyst layer,the maximum power density of fuel cell increases by 10%without any additional durability loss while maintaining a similar electrochemical surface area.The concentration contours calculated by finite element analysis reveal that the grooves built on the surface of catalyst layer serve to accumulate the water nearby while oxygen tends to transfer through relatively convex region,which results from capillary pressure difference caused by the pore structure difference between the two regions.The separation of oxidant gas and generated water avoids mass confliction thus boosts mass transport efficiency.

Layered Software Patterns for Data Analysis in Big Data Environment

The proliferation of textual data in society currently is overwhelming, in particular, unstructured textual data is being constantly generated via call centre logs, emails, documents on the web, blogs, tweets, customer comments, customer reviews, etc.While the amount of textual data is increasing rapidly, users ability to summarise, understand, and make sense of such data for making better business/living decisions remains challenging. This paper studies how to analyse textual data, based on layered software patterns, for extracting insightful user intelligence from a large collection of documents and for using such information to improve user operations and performance.

High-resolution, full-color quantum dot light-emitting diode display fabricated via photolithography approach

Displays play an extremely important role in modern information society,which creates a never-ending demand for the new and better products and technologies.The latest requirements for novel display technologies focus on high resolution and high color gamut.Among emerging technologies that include organic light-emitting diode(OL ED),micro light-emiting diode(micro-LED),quantum dot light-emitting diode(QLED),laser display,holographic display and others,QLED is promising owing to its intrinsic high color gamut and the possibility to achieve high resolution with photolithography approach.However,previously demonstrated photolthography techniques suffer from reduced device performance and color Impurities in subpixels from the process.In this study,we demonstrated a sacrificial layer assisted patterming(SLAP)approach,which can be applied in conjunction with photolithography to fabricate high-resolution,full-colo quantum dot(QD)patterns.In this approach,the negative photoresist(PR)and sacrificial layer(SL)were uilized to determine the pixels for QD deposition,while at the same time the SL helps protect the QD layer and keep it intact(named PR-SL approach).To prove this method's viability for QLED display manufacture,a 500-ppi,full-color passive matrix(PM)-QLED prototype was fabricated via this process.Results show that there were no color impurities in the subpixels,and the PM-QL ED has a high color gamut of 114%National Television Standards Committee(NTSC).To the best of our knowledge,this is the first ull-olor QLED prototype with such a high resolution.We anticipate that this innovative patteming technique will open a new horizon for future display technologies and may lead to a disruptive and innovative change in display industry.