Enhanced electrochromic switching contrast in the blue by 3,4-propylenedioxypyrrole - Implementation on structural colors

Recent advances in nanofabrication technologies have enabled new ways to produce structural colors. By combining nanofabrication methods, it is possible to integrate electrochromic materials with the nanostructures, which enable electrical tuning of the colors and thus new types of reflective displays. Previous work has shown high quality colors and high switching contrast in general. However, so far the intensity modulation has always been more limited in the blue. In this work we prepare blue structural colors and synthesize films of an electrochromic polymer (PProDOP) that is optimized for high contrast in this spectral region. A protocol for electropolymerization of PProDOP on gold surfaces is presented. The polymer films are shown to follow Lambert-Beer behavior and can provide up to 75% contrast (difference in transmittivity). On blue nanostructures, the reflectivity can be modulated with a contrast of 50%, which is a considerable improvement in comparison with previous work. The results presented here should be useful for electrochromic or other electro-optical devices operating in the blue spectral region

Produktivitet och kvalitet vid stickvägs- respektive beståndsgående förstagallring

Nowadays the majority of the thinnings made in Swedish forests are done by machines, harvesters and forwarders. The most common model in thinning with a harvester is strip-road operated thinning and stand-operated thinning with one intermediate passage between the strip-roads. This study is a time study with some quality follow ups on a strip-road operated thinning model, a stand-operated thinning model with one intermediate passage between the strip-roads and a stand-operated thinning model with two intermediate passages between the strip-roads. The machines in the study were a small harvester (Forestline MPM C90) and a medium sized forwarder (Timberjack 1110). The study was made in Litsnäset outside the city of Östersund in Sweden and was made during the autumn 2007. In a lodgepole pine stand six study units (0,6 ha) were thinned with the three different models, two study units per model. After the thinning was done two loads of timber per study units were forwarded out. The results of the study showed that the performance of the harvester was similar when working with the stand-operated thinning models compared to the strip-road operated thinning model. The difference in performance between the three types of thinning models was not significant. The results for the forwarder showed that the difference in performance was significant between the models that were thinned with the stand-operated models and the strip-road operated model and it performed by far best in the model that was thinned with the stand-operated thinning with two intermediate passages between the strip-roads. The quality follow up showed that the strip-road operated thinning model left fewer damaged trees in the remaining forest than the other two stand-operated thinning models. However, the stand-operated thinning models had a smaller strip-road area. The financial analysis showed that the cutting costs for both machines were highest in strip-road operated thinning with 120,8 SEK/m³fub compared to 120,3 SEK/m³fub and 118,6 SEK/m³fub in stand-operated thinning with one and two, respectively, intermediate passages between the strip-roads.Idag gallras den allra största delen av våra skogar maskinellt utan motormanuell huggning. De vanligaste tillvägagångssätten att gallra är stickvägsgående och beståndsgående med ett stråk mellan stickvägarna. I denna studie gjordes en tidsstudie och kvalitetsuppföljning på de tidigare nämnda metoderna samt beståndsgående gallring med två stråk mellan stickvägarna. Maskinerna som studerades var en liten beståndsgående skördare av märket Forestline MPM C90 och en Timberjack 1110 skotare. I ett contortabestånd snitslades sex stycken parceller in på vardera 0,6 ha. Dessa sex parceller gallrades med de olika metoderna, två på vardera sätt. Därefter skotades två lass ut per parcell. Under gallringen och skotningen utfördes en tidsstudie med en handdator av märket Allegro CE. Efter utförd gallring och skotning gjordes kvalitetsmätningar i parcellerna. Studien genomfördes i Litsnäset utanför Östersund i Jämtland under hösten 2007. Resultatet visade att det inte fanns någon signifikant skillnad i skördarproduktivitet mellan de tre olika gallringsmodellerna. För skotaren var det däremot en signifikant skillnad i produktivitet mellan de parceller som gallrats beståndsgående och stickvägsgående, där högst produktivitet nåddes i de bestånd som gallrades med två stråk mellan stickvägarna. Den ekonomiska analysen visade att avverkningskostnaden för hela maskinsystemet var dyrast i den stickvägsgående modellen med 120,8 kr/m³fub för stickvägsgående, och 120,3 kr/m³fub för beståndsgående med ett stråk och 118,6 kr/m³fub för beståndsgående med två stråk. Kvalitetsuppföljningen visade att gallringsmodellen med stickvägsgående gallring gav lägst andel skador på kvarvarande träd men högst andel stickvägsareal

Sequential Monte Carlo Methods for System Identification

One of the key challenges in identifying nonlinear and possibly non-Gaussian state space models (SSMs) is the intractability of estimating the system state. Sequential Monte Carlo (SMC) methods, such as the particle filter (introduced more than two decades ago), provide numerical solutions to the nonlinear state estimation problems arising in SSMs. When combined with additional identification techniques, these algorithms provide solid solutions to the nonlinear system identification problem. We describe two general strategies for creating such combinations and discuss why SMC is a natural tool for implementing these strategies.Comment: In proceedings of the 17th IFAC Symposium on System Identification (SYSID). Added cover pag

Accurate Correction of the "bulk Response" in Surface Plasmon Resonance Sensing Provides New Insights on Interactions Involving Lysozyme and Poly(ethylene glycol)

Surface plasmon resonance is a very well-established surface sensitive technique for label-free analysis of biomolecular interactions, generating thousands of publications each year. An inconvenient effect that complicates interpretation of SPR results is the "bulk response"from molecules in solution, which generate signals without really binding to the surface. Here we present a physical model for determining the bulk response contribution and verify its accuracy. Our method does not require a reference channel or a separate surface region. We show that proper subtraction of the bulk response reveals an interaction between poly(ethylene glycol) brushes and the protein lysozyme at physiological conditions. Importantly, we also show that the bulk response correction method implemented in commercial instruments is not generally accurate. Using our method, the equilibrium affinity between polymer and protein is determined to be KD = 200 μM. One reason for the weak affinity is that the interaction is relatively short-lived (1/koff < 30 s). Furthermore, we show that the bulk response correction also reveals the dynamics of self-interactions between lysozyme molecules on surfaces. Besides providing new insights on important biomolecular interactions, our method can be widely applied to improve the accuracy of SPR data generated by instruments worldwide

Tuning the Thermoresponsive Behavior of Surface-Attached PNIPAM Networks: Varying the Crosslinker Content in SI-ATRP

The synthesis and thermoresponsive properties of surface-attached poly(N-isopropylacrylamide)-co-N,N′-methylene bisacrylamide (PNIPAM-co-MBAM) networks are investigated. The networks are formed via SI-ARGET-ATRP ("grafting-from") on thiol-based initiator-functionalized gold films. This method is reliable, well controlled, fast, and applicable to patterned surfaces (e.g., nanopores) for networks with dry thicknesses >20 nm. Surface-attached PNIPAM-co-MBAM gels are swollen below their volume phase transition temperature but above collapse without complete expulsion of water (retain ∼50 vol %). The swelling/collapse transition is studied using complementary SPR and QCMD techniques. The ratio between swollen and collapsed heights characterizes the thermoresponsive behavior and is shown to not depend on network height but to vary with MBAM content. The higher the proportion of the crosslinker, the lower the magnitude of the phase transition, until all responsiveness is lost at 5 mol % MBAM. The temperature range of the transition is broadened for more crosslinked PNIPAM-co-MBAM gels but remains centered around 32 \ub0C. Upon reswelling, less crosslinked networks display sharp transitions, while for those containing ≥3 mol % MBAM, transitions remain broad. This tunable behavior persists for gels on nanostructured gold surfaces. Investigating PNIPAM-co-MBAM networks on gold plasmonic nanowell arrays is a starting point for expanding their scope as thermo-controlled nanoactuators

Large Changes in Protonation of Weak Polyelectrolyte Brushes with Salt Concentration-Implications for Protein Immobilization

We report for the first time that the protonation behavior of weak polyelectrolyte brushes depends very strongly on ionic strength. The pKa changes by one pH step per order of magnitude in salt concentration. For low salt concentrations (∼1 mM), a very high pH is required to deprotonate a polyacidic brush and a very low pH is required to protonate a polybasic brush. This has major consequences for interactions with other macromolecules, as the brushes are actually almost fully neutral when believed to be charged. We propose that many previous studies on electrostatic interactions between polyelectrolytes and proteins have, in fact, looked at other types of intermolecular forces, in particular, hydrophobic interactions and hydrogen bonds

Interfacing and scheduling legacy code within the Canals framework

International audienceThe need for understanding how to distribute computations across multiple cores, have obviously increased in the multi-core era. Scheduling the functional blocks of an application for concurrent execution requires not only a good understanding of data dependencies, but also a structured way to describe the intended scheduling. In this paper we describe how the Canals language and its scheduling framework can be used for the purpose of scheduling and executing legacy code. Additionally a set of translation guidelines for translating RVC-CAL applications into Canals are presented. The proposed approaches are applied to an existing MPEG-4 Simple Profile decoder for evaluation purposes. The inverse discrete cosine transform (IDCT) is accelerated by the means of OpenCL

Electrochromic Inorganic Nanostructures with High Chromaticity and Superior Brightness

The possibility of actively controlling structural colors has recently attracted a lot of attention, in particular for new types of reflective displays (electronic paper). However, it has proven challenging to achieve good image quality in such devices, mainly because many subpixels are necessary and the semitransparent counter electrodes lower the total reflectance. Here we present an inorganic electrochromic nanostructure based on tungsten trioxide, gold, and a thin platinum mirror. The platinum reflector provides a wide color range and makes it possible to "reverse"the device design so that electrolyte and counter electrode can be placed behind the nanostructures with respect to the viewer. Importantly, this makes it possible to maintain high reflectance regardless of how the electrochemical cell is constructed. We show that our nanostructures clearly outperform the latest commercial color e-reader in terms of both color range and brightness

Rialto 2.0: A Language for Heterogeneous Computations

International audienceModern embedded systems are often heterogeneous in that their design requires several description paradigms, based on different models of computation and concurrency (MoCCs). In this paper we present Rialto, a formal language intended at expressing computations in several MoCCs. The distinguishing features of Rialto and its implementation are 1) A formal semantics: the language is formalized using SOS (structured operational semantics) rules; 2) Encapsulation of models of computation into policies: we thus distinguish between the syntactic elements of the language (parallelism, interrupts) and its semantics; 3) efficient implementation algorithms. Policies are expressed in the language itself, which allows for more expressive power and a sounder semantics

Generic high-capacity protein capture and release by pH control

Techniques for immobilization and release of proteins are of general interest but challenging to develop. Here we show a new method for high-capacity (several \ub5g cm-2) immobilization of proteins in polyelectrolyte brushes by multivalent hydrogen bonds. Upon increasing pH, the proteins are fully released with preserved structure and activity