Polynomial fitting of interferograms with Gaussian errors on fringe coordinates. 1: Computer simulations

A series of simulations were made for an ideal Twyman-Green interferogram of equally spaced straight fringes having tilt only about x. It was found that fitting polynomials to the interferometric data resulted in biased estimates of some of the fitting coefficients to the optical path difference. The acceptance of the Seidel aberrations grows with the noise level and diminishes when the number of fringes is increased.     

Characterization of conductive multiwall carbon nanotube/polystyrene composites prepared by latex technology

Conductive multiwall carbon nanotube/polystyrene (MWCNT/PS) composites are prepared based on latex technology. MWCNTs are first dispersed in aqueous solution of sodium dodecyl sulfate (SDS) driven by sonication and then mixed with different amounts of PS latex. From these mixtures MWCNT/PS composites were prepared by freeze-drying and compression molding. The dispersion of MWCNTs in aqueous SDS solution and in the PS matrix is monitored by UV–vis, transmission electron microscopy, electron tomography and scanning electron microscopy. When applying adequate preparation conditions, MWCNTs are well dispersed and homogeneously incorporated in the PS matrix. The percolation threshold for conduction is about 1.5 wt% of MWCNTs in the composites, and a maximum conductivity of about 1 S m⁻¹ can be achieved. The approach presented can be adapted to other MWCNT/polymer latex systems.     

Prediction of NOx Emissions from a Transiently Operating Diesel Engine Using an Artificial Neural Network

For an adequate control of the reductant flow in selective catalytic reduction of NO_x in diesel exhaust, a tool has to be available to accurately and quickly predict the engine's NO_x emission. For these purposes, elaborate computer models and expensive NO_x analyzers are not feasible. The application of a neural network is proposed instead. Measurements were performed on a transient operating diesel engine. One part of the data was used to train the network for NO_x emission prediction, the other part was used to test. The average absolute deviation between the predicted and measured NO_x emission is 6.7 %. The reductant buffering capacity of the deNOx catalyst will diminish the effect of the deviation on the overall NO_x removal efficiency. The high accuracy of the neural network predictions, combined with the short computation times (0.2 ms/data point), makes the neural network a very promising tool in automotive NO_x control.     

Reductant flow control for NOX removal from lean exhaust gases

This review article describes and discusses the literature on reducing agent control systems for NO_x emission reduction in the exhaust gas of full lean‐burn engines. The literature can be classified as feedback, feedforward, feedforward‐feedback, feedforward/feedforward‐feedback and periodical dosing control systems, which can be further classified as classical, override, co‐ordinated, constrained and split systems or a combination of those. As long as reproducible, fast and cheap NO_x sensors are not commercially available, the control system should be an inferential feedforward or feedforward‐feedback system supplied with constraints for environmental and economical reasons. For future applications an oxidation catalyst downstream of the deNO_x catalyst should be applied to convert any inevitable reductant slip, due to modelling errors, to harmless compounds.     

Involvement of Virus-Induced Interferon Production in IgG Autoantibody-Mediated Anemia

Infection with viruses, such as the lactate dehydrogenase-elevating virus (LDV), is known to trigger the onset of autoimmune anemia through the enhancement of the phagocytosis of autoantibody-opsonized erythrocytes by activated macrophages. Type I interferon receptor-deficient mice show enhanced anemia, which suggests a protective effect of these cytokines, partly through the control of type II interferon production. The development of anemia requires the expression of Fcγ receptors (FcγR) I, III, and IV. Whereas LDV infection decreases FcγR III expression, it enhances FcγR I and IV expression in wild-type animals. The LDV-associated increase in the expression of FcγR I and IV is largely reduced in type I interferon receptor-deficient mice, through both type II interferon-dependent and -independent mechanisms. Thus, the regulation of the expression of FcγR I and IV, but not III, by interferons may partly explain the exacerbating effect of LDV infection on anemia that results from the enhanced phagocytosis of IgG autoantibody-opsonized erythrocytes.     

Biobased step-growth polymers in powder coating applications

Co- and terpolyesters based on 1,4:3,6-dianhydro-d-glucitol (isosorbide), 1,4:3,6-dianhydro-l-iditol (isoidide) and succinic acid were evaluated for their applicability in solvent-cast and powder coatings. These biobased polyesters have functionalities and T_g values in the appropriate range for such applications and were cross-linked using conventional curing agents. Introduction of poly-functional monomers such as glycerol and citric acid led to coatings with enhanced performance with respect to mechanical and chemical resistance, compared to formulations based on linear polymers. The curing behavior of these systems was investigated with DSC and rheological experiments. Formulations containing citric acid-modified polyester resins showed rapid curing, probably facilitated by anhydride formation at the chain ends. Hydroxy- as well as carboxylic acid-functional 1,4:3,6-dianhydrohexitol-based polyesters proved to be suitable materials for coating applications with respect to solvent resistance, impact resistance and hardness, with performance comparable to commercially available systems. Accelerated weathering experiments showed that functional groups such as hydroxyl groups, carboxylic acids, anhydrides and peroxides are formed during UV-exposure. The weathered coatings have reduced impact stability. On the other hand, the appearance of the coatings does not change significantly. Isosorbide-based coating systems appear to have similar weathering resistance as conventional terephthalic acid-based poly(ester urethane) coatings.     

Parallel Scalability of Video Decoders

An important question is whether emerging and future applications exhibit sufficient parallelism, in particular thread-level parallelism, to exploit the large numbers of cores future chip multiprocessors (CMPs) are expected to contain. As a case study we investigate the parallelism available in video decoders, an important application domain now and in the future. Specifically, we analyze the parallel scalability of the H.264 decoding process. First we discuss the data structures and dependencies of H.264 and show what types of parallelism it allows to be exploited. We also show that previously proposed parallelization strategies such as slice-level, frame-level, and intra-frame macroblock (MB) level parallelism, are not sufficiently scalable. Based on the observation that inter-frame dependencies have a limited spatial range we propose a new parallelization strategy, called Dynamic 3D-Wave. It allows certain MBs of consecutive frames to be decoded in parallel. Using this new strategy we analyze the limits to the available MB-level parallelism in H.264. Using real movie sequences we find a maximum MB parallelism ranging from 4000 to 7000. We also perform a case study to assess the practical value and possibilities of a highly parallelized H.264 application. The results show that H.264 exhibits sufficient parallelism to efficiently exploit the capabilities of future manycore CMPs.

Understanding temperature dependency of hydrogen solubility in ionic liquids,including experimental data in [bmim][Tf2N]

Previously unavailable high‐pressure solubility data of hydrogen in 1‐butyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)amide has been measured experimentally up to temperatures and pressures of 450 K and 15 MPa, respectively. In contrast to CO₂ solubility, H₂ tends to dissolve better in the ionic liquid at higher temperatures. This “inverse” temperature effect has been studied from a thermodynamic perspective and the underlying reason for this effect is explained. It is shown that the negative P‐T slope is not limited to this particular binary mixture, but is the typical behavior in most, if not all, H₂ + ionic liquid systems. However, there is a certain range of temperatures, pressures, and concentrations in which this phenomenon occurs. By predicting the Scott‐van Konynenburg phase diagram for systems of H₂ + ionic liquids to be of type III, it is shown how and why the solubility increases with temperature in some regions, but decreases in others. © 2012 American Institute of Chemical Engineers AIChE J, 2012     

High‐Conductivity Polymer Nanocomposites Obtained by Tailoring the Characteristics of Carbon Nanotube Fillers

We present a detailed study of the influence of carbon nanotube (CNT) characteristics on the electrical conductivity of polystyrene nanocomposites produced using a latex‐based approach. We processed both industrially‐produced multi‐wall CNT (MWCNT) powders and MWCNTs from vertically‐aligned films made in‐house, and demonstrate that while the raw CNTs are individualized and dispersed comparably within the polymer matrix, the electrical conductivity of the final nanocomposites differs significantly due to the intrinsic characteristics of the CNTs. Owing to their longer length after dispersion, the percolation threshold observed using MWCNTs from vertically‐aligned films is five times lower than the value for industrially‐produced MWCNT powders. Further, owing to the high structural quality of the CNTs from vertically‐aligned films, the resulting composite films exhibit electrical conductivity of 10³ S m^?1 at 2 wt% CNTs. On the contrary, composites made using the industrially‐produced CNTs exhibit conductivity of only tens of S m^?1. To our knowledge, the measured electrical conductivity for CNT/PS composites using CNTs from vertically‐aligned films is by far the highest value yet reported for CNT/PS nanocomposites at this loading.     

英日自动翻译系统中基于P-树到D-树转换的的生成模块

本文的内容是在1998年中文信息处理国际会议小组讨论上发表的基础上加工而成。本文主要讨论了我公司最近研发的英日自动翻译系统中日语生成模块的一些理论和实践问题。主要包括以下几个内容: 1. 语法过滤机制:是该生成模块的开发的核心思想; 2. 格助词的处理问题,这是日文生成成败的关键问题; 3. 核心句转换:整个生成过程就是一个从非核心句到核心句的转换过程; 4. 助动词的处理,P-树结构向D-树结构转换的重要组成部分; 5. 否定结构的处理,是该生成模块最困难的问题之一。