Charge Transport in Disordered Organic Materials and Its Relevance to Thin‐Film Devices: A Tutorial Review

Semiconducting polymers and small molecules form an extremely flexible class of amorphous materials that can be used in a wide range of applications, some of which are display, radio‐frequency tags, and solar cells. The rapid progress towards functional devices is occurring despite the lack of sufficient understanding of the physical processes and very little experience in device engineering. This tutorial review aims to provide sufficient intuitive background to draw more researchers to look into the fundamental aspects of device physics and engineering.     

Mesh-of-Trees and Alternative Interconnection Networks for Single-Chip Parallelism

In single-chip parallel processors, it is crucial to implement a high-throughput low-latency interconnection network to connect the on-chip components, especially the processing units and the memory units. In this paper, we propose a new mesh of trees (MoT) implementation of the interconnection network and evaluate it relative to metrics such as wire complexity, total register count, single switch delay, maximum throughput, tradeoffs between throughput and latency, and post-layout performance. We show that on-chip interconnection networks can provide higher bandwidth between processors and shared first-level cache than previously considered possible, facilitating greater scalability of memory architectures that require that. MoT is also compared, both analytically and experimentally, to some other traditional network topologies, such as hypercube, butterfly, fat trees and butterfly fat trees. When we evaluate a 64-terminal MoT network at 90-nm technology, concrete results show that MoT provides higher throughput and lower latency especially when the input traffic (or the on-chip parallelism) is high, at comparable area. A recurring problem in networking and communication is that of achieving good sustained throughput in contrast to just high theoretical peak performance that does not materialize for typical work loads. Our quantitative results demonstrate a clear advantage of the proposed MoT network in the context of single-chip parallel processing.     

Understanding the Role of Alumina (Al2O3), Pentalithium Aluminate (Li5AlO4), and Pentasodium Aluminate (Na5AlO4) Coatings on the Li and Mn-Rich NCM Cathode Material 0.33Li2MnO3·0.67Li(Ni0.4Co0.2Mn0.4)O2 for Enhanced Electrochemical Performance

The active role of alumina, pentalithium aluminate (Li₅AlO₄, Li-aluminate), and pentasodium aluminate (Na₅AlO₄, Na-aluminate) as the surface protection coatings produced via atomic layer deposition on Li and Mn-rich NCM cathode materials 0.33Li₂MnO₃·0.67LiNi_0.4Co_0.2Mn_0.4O₂ is discussed. A notable improvement in the electrochemical behavior of the coated cathodes has been found while tested in Li-coin cells at 30 °C. Though all the coated cathodes demonstrate enhanced electrochemical cycling and rate performances, Na-aluminate coated cathodes exhibit exemplary behavior. Prolonged cycling and rate capability testing demonstrate that after more than 400 cycles at 1 C rate, the uncoated cathode delivers only 63 mAh g⁻¹, while those with alumina, Li-aluminate, and Na-aluminate coatings exhibit approximately two times higher specific capacities. The coated cathodes display steady average discharge potential and lower evolution of the voltage hysteresis during prolonged cycling compared to the uncoated cathode. Importantly, Na-aluminate coated cathode shows a lowering in gases (O₂, CO₂, H₂, etc.) evolution. Post-cycling analysis of the electrodes demonstrates higher morphological integrity of the coated cathode materials and lower transition metals dissolution from them. The coatings mitigate undesirable side reactions between the electrodes and the electrolyte solution in the cells.     

To call or not to call—That is the question (while driving)

We studied whether decisions to engage in cell phone conversation while driving and the consequences of such decisions are related to the driver's age, to the road conditions (demands of the driving task), and to the driver's role in initiating the phone call (i.e. the driver as caller vs. as receiver). Two experiments were performed in a driving simulator in which driver age, road conditions and phone conversation, as a secondary task, were manipulated. Engagement in cell phone conversations, performance in the driving and the conversation tasks, and subjective effort assessment were recorded. In general, drivers were more willing to accept incoming calls than to initiate calls. In addition, older and younger drivers were more susceptible to the deleterious effects of phone conversations while driving than middle aged/experienced drivers. While older drivers were aware of this susceptibility by showing sensitivity to road conditions before deciding whether to engage in a call or not, young drivers showed no such sensitivity. The results can guide the development of young driver training programs and point at the need to develop context-aware management systems of in-vehicle cell phone conversations.     

Advances in Polyimide‐Based Materials for Space Applications

The space environment raises many challenges for new materials development and ground characterization. These environmental hazards in space include solar radiation, energetic particles, vacuum, micrometeoroids and debris, and space plasma. In low Earth orbits, there is also a significant concentration of highly reactive atomic oxygen (AO). This Progress Report focuses on the development of space‐durable polyimide (PI)‐based materials and nanocomposites and their testing under simulated space environment. Commercial PIs suffer from AO‐induced erosion and surface electric charging. Modified PIs and PI‐based nanocomposites are developed and tested to resist degradation in space. The durability of PIs in AO is successfully increased by addition of polyhedral oligomeric silsesquioxane. Conductive materials are prepared based on composites of PI and either carbon nanotube (CNT) sheets or 3D‐graphene structures. 3D PI structures, which can expand PI space applications, made by either additive manufacturing (AM) or thermoforming, are presented. The selection of AM‐processable engineering polymers in general, and PIs in particular, is relatively limited. Here, innovative preliminary results of a PI‐based material processed by the PolyJet technology are presented.     

Degree distribution of the FKP network model

Power laws, in particular power-law degree distributions, have been observed in real-world networks in a very wide range of contexts, including social networks, biological networks, and artificial networks such as the physical internet or abstract world wide web. Recently, these observations have triggered much work attempting to explain the power laws in terms of new ‘scale-free’ random graph models. So far, perhaps the most effective mechanism for explaining power laws is the combination of growth and preferential attachment. In [A. Fabrikant, E. Koutsoupias, C.H. Papadimitriou, Heuristically optimized trade-offs: A new paradigm for power laws in the internet ICALP 2002, in: LNCS, vol. 2380, pp. 110–122], Fabrikant, Koutsoupias and Papadimitriou propose a new ‘paradigm’ for explaining power laws, based on trade-offs between competing objectives. They also introduce a new, simple and elegant parametrized model for the internet, and prove some kind of power-law bound on the degree sequence for a wide range of scalings of the trade-off parameter.     

Correlations (updated) for predicting the flow through MSF plant interstage orifices

So far, very few design correlations for interstage flow in MSF plants have been published, and their validation for a broad range of conditions is absent. Based on all experimental data with small-scale MSF units that was available to us, correlations for the orifice coefficient were developed for a wide range of flow and flashing conditions, in stages without and with downstream baffles, and a draft was presented at a past IDA congress. This paper recorrelates them in a much better way. These correlations are the first to use such a large amount of data, and the first to employ appropriate dimensionless variables. While their standard error and correlation coefficient are satisfactory, we note that the data came from a variety of sources and for channel widths of at most 0.53 m. Consequently, they should be used with some caution, and further extensive well-instrumented experiments are highly recommended.     

有线与无线802.11家庭网络

无线家庭网络正在成为家庭中新兴的数据服务传输技术。802．11b的价格与有线解决方案不相上下，并且无需任何连线即可在实现互联，对那些希望在家庭中铺设网络的用户来说是很好的选择。企业市场对802．11b产品的需求非常高，这推动了其价格进一步下降，并提供了家庭和公司网络共同的接口，从而使其作为家庭网络技术更具有吸引力。