On the Relation between Morphology and FET Mobility of Poly(3‐alkylthiophene)s at the Polymer/SiO2 and Polymer/Air Interface

The influence of the interface of the dielectric SiO₂ on the performance of bottom‐contact, bottom‐gate poly(3‐alkylthiophene) (P3AT) field‐effect transistors (FETs) is investigated. In particular, the operation of transistors where the active polythiophene layer is directly spin‐coated from chlorobenzene (CB) onto the bare SiO₂ dielectric is compared to those where the active layer is first spin‐coated then laminated via a wet transfer process such that the film/air interface of this film contacts the SiO₂ surface. While an apparent alkyl side‐chain length dependent mobility is observed for films directly spin‐coated onto the SiO₂ dielectric (with mobilities of ≈10^?3 cm² V^?1 s^?1 or less) for laminated films mobilities of 0.14 ± 0.03 cm² V^?1 s^?1 independent of alkyl chain length are recorded. Surface‐sensitive near edge X‐ray absorption fine structure (NEXAFS) spectroscopy measurements indicate a strong out‐of‐plane orientation of the polymer backbone at the original air/film interface while much lower average tilt angles of the polymer backbone are observed at the SiO₂/film interface. A comparison with NEXAFS on crystalline P3AT nanofibers, as well as molecular mechanics and electronic structure calculations on ideal P3AT crystals suggest a close to crystalline polymer organization at the P3AT/air interface of films from CB. These results emphasize the negative influence of wrongly oriented polymer on charge carrier mobility and highlight the potential of the polymer/air interface in achieving excellent “out‐of‐plane” orientation and high FET mobilities.     

Comparison of the performances of Nero Siciliano pigs reared indoors and outdoors. 1. Growth and carcass composition

A total of 78 female and male Nero Siciliano pigs were used. Forty-one pigs were reared following the traditional management system, 37 pigs were reared in pens with a small outdoor paddock and fed to appetite using commercial rations according to the growing period. Both male and female pigs were castrated. All pigs were weighed and measured periodically. Body measurements included height at withers, chest girth, body length, width at shoulders and at rump. Age and body weight at slaughter ranged respectively from 371 to 572 days and from 79 to 113 kg. The carcasses were weighed and dissected into lean, fat and bone cuts. In the early and final stages indoor-pigs grew faster than those reared outdoors. Trends in body length were similar for the two rearing systems, for width at shoulders and rump, chest girth and height at withers, indoor pigs showed higher values than the outdoor ones. Carcasses of similar weight were longer in outdoor than in indoor pigs but the latter showed greater subcutaneous fat thickness. Outdoor pigs had the lowest dressing percentage and the highest percentage of lean cuts, such as shoulder and ham, but not of neck and loin. Sex did not significantly affect the analysed characteristics.     

Catalytic Synergism in a C60IL10TEMPO2 Hybrid in the Efficient Oxidation of Alcohols

A novel fullerene [5:1]hexakisadduct bearing two 2,2,6,6‐tetramethylpiperidine 1‐oxyl (TEMPO) radicals and ten 1‐propyl‐3‐methylimidazolium bromide moieties has been synthesized and characterized. Such an C₆₀IL₁₀TEMPO₂ hybrid has been successfully employed as a catalyst in the selective oxidation of a wide series of alcohols and is highly active at just 0.1 mol% loading. Moreover, it can be easily recovered by adsorption onto a multi‐layered covalently‐linked SILP phase (mlc‐SILP) through a “release and catch” approach and reused for up to 12 cycles without loss in efficiency. Interestingly, a catalytic synergistic effect of TEMPO and imidazolium bromide moieties combined in the same hybrid has been clearly shown.

     

Multi‐dimensional modeling of solar cells with electromagnetic and carrier transport calculations

We present a multi‐dimensional model for comprehensive simulations of solar cells (SCs), considering both electromagnetic and electronic properties. Typical homojunction and heterojunction gallium arsenide SCs were simulated in different spatial dimensions. When considering one‐dimensional problems, the model performs carrier transport calculations following a Beer–Lambert optical absorption approximation. We show that the results of such simulations exhibit excellent agreement with the standard PC1D one‐dimensional photovoltaic simulation. Photonic and plasmonic attempts to enhance SC efficiency demand comprehensive electromagnetic calculations to be undertaken in order to acquire accurate carrier generation profiles in two and three‐dimensional systems. Our model provides complete spectral and spatial information of typical optical and electronic behavior. Furthermore, our approach permits the detailed investigation of complex systems, including plasmonic SCs, which cannot be simulated using low‐dimensional modeling tools. We present the results of numerical simulations of an optically thin plasmonic gallium arsenide SC and observe improved device performance arising from the application of plasmonic nanostructures, which agree well with previous experimental findings. Copyright © 2012 John Wiley & Sons, Ltd.     

Degradation of lincomycin in aqueous medium: Coupling of solar photocatalysis and membrane separation

The photocatalytic oxidation of a common antibiotic, the lincomycin was carried out in aqueous suspensions of polycrystalline TiO₂ Degussa P25 irradiated by sunlight. In order to improve the performance of the lincomycin degradation a hybrid system consisting of a solar photoreactor with the photocatalyst in suspension coupled with a membrane module, used to confine both photocatalyst and pollutants in the reaction environment, was tested.A preliminary study was carried out in order to determine some kinetics parameters of the drug photodegradation. The influence of initial substrate concentration on the lincomycin photooxidation rate was investigated. The photooxidation rate follows a pseudo-first order kinetics with respect to the lincomycin concentration under the used experimental conditions. The presence of the membrane reactor allows the catalyst separation and to operate in continuous mode as the membranes rejection for lincomycin and its oxidation products was quite high.     

Hyperazeotropic ethanol salted-out by extractive distillation. Theoretical evaluation and experimental check

A distillation process for the production of hyperazeotropic ethanol from a dilute wine obtained from the fermentation of biomass has been studied. This process utilizes the coupling of a soft preconcentration stage and of a dehydration stage based on the salting-out effect produced by calcium chloride on the ethanol in an aqueous solution, with the disappearance of the azeotrope. The salt is employed in a close cycle, due to the presence of a regeneration stage, therefore no consumption of calcium chloride is noticed.

The distillation process utilizes one column consisting of two sections operating at different pressures in order to reach an efficient heat recovery.

In this paper, a simplified flow-sheet of the process and the principal operating conditions of the distillation column are illustrated. When compared with other processes, conventional or under development, this one is characterized by the promising reduction of the specific energy requirement.

The operating conditions chosen for the distillation with salt have been experimentally checked using a laboratory column running continuously with calcium chloride as salting-out agent. Moreover, the experiments confirmed the reliability of the mathematical model of the process. Further experiments are in progress with the aim of utilizing a mixture of salts which can be fed from the bottom of the dehydration section back to the fermentor, so that the salt regeneration stage can be reduced.     

On the Systematic Analysis of Natural Language Requirements with CIRCE

This paper presents Circe, an environment for the analysis of natural language requirements. Circe is first presented in terms of its architecture, based on a transformational paradigm. Details are then given for the various transformation steps, including (i) a novel technique for parsing natural language requirements, and (ii) an expert system based on modular agents, embodying intensional knowledge about software systems in general. The result of all the transformations is a set of models for the requirements document, for the system described by the requirements, and for the requirements writing process. These models can be inspected, measured, and validated against a given set of criteria. Some of the features of the environment are shown by means of an example. Various stages of requirements analysis are covered, from initial sketches to pseudo-code and UML models.     

Digital Median Filters

Several DSP algorithms need to remove high-frequency or impulsive noise while preserving edges, e.g., in speech and image processing applications: median filtering has been proved to be more effective for achieving this goal than other filtering techniques. Efficient architectural implementation for real-time applications involves a careful VLSI design, which takes into account modularity, regularity, adaptability, scalability, throughput, circuit complexity and fault tolerance. Four new architectural approaches are presented and evaluated in this paper to deal with different application and implementation constraints. They are: the serial-input polarizing median filter, the floating median filter, the pipelined polarizing median filter and the pipelined sorting median filter. The 1st and the 2nd architectures are based on majority voting, while the 3rd and the 4th ones are based on sorting techniques. All of them are designed so as to exhibit high scalability and to be easily pipelined for higher working frequencies.     

Tuning the Dimensions of C60‐Based Needlelike Crystals in Blended Thin Films

A new ordered structure of the C₆₀ derivative PCBM ([6‐6]‐phenyl C₆₁‐butyric acid methyl ester) is obtained in thin films based on the blend PCBM:regioregular P3HT (poly(3‐hexylthiophene)). Rapid formation of needlelike crystalline PCBM structures of a few micrometers up to 100 μm in size is demonstrated by submitting the blended thin films to an appropriate thermal treatment. These structures can grow out to a 2D network of PCBM needles and, in specific cases, to spectacular PCBM fans. Key parameters to tune the dimensions and spatial distribution of the PCBM needles are blend ratio and annealing conditions. The as‐obtained blended films and crystals are probed using atomic force microscopy, transmission electron microscopy, selected area electron diffraction, optical microscopy, and confocal fluorescence microscopy. Based on the analytical results, the growth mechanism of the PCBM structures within the film is described in terms of diffusion of PCBM towards the PCBM crystals, leaving highly crystalline P3HT behind in the surrounding matrix.     

塔菜克·纳卡:空间思想的自由和严密

我首先想要对读者表明我对建筑学的观点。我试图强调如何将理念融入到空间的创造中。这不仅仅是一个建筑学问题，而且是全人类表达的一个组成部分。对于那些问“一个好建筑师需要研究些什么？”的人，有人回答是技术、有人回答是造型、还有人回答是形体学问题等等。我个人的感觉是：人，这个观点也被其他很多思索者所认同。我们再一次地发现，如果我们探寻什么，真理要比它看起来遥远得多，有时甚至看不到，而且从不确定和讨人喜欢。