Compensation-based control for lossy communication networks

In this paper, we are concerned with the stability analysis and the design of stabilising compensation-based control algorithms for networked control systems (NCSs) that exhibit packet dropouts. In order to increase the robustness against packet dropouts for such NCSs, we propose a new type of model-based dropout compensator, which depends on the local dropout history. Moreover, we provide linear matrix inequality based synthesis conditions for such compensators guaranteeing robust stability. The analysis and design framework includes both worst-case-bound and stochastic models to describe the packet-dropout behaviour in both the sensor-to-controller and the controller-to-actuator channels. Numerical examples demonstrate the significantly improved robustness with respect to packet dropouts using the proposed dropout compensator, compared to using the existing zero strategy and the hold strategy.     

Wear out failure mechanisms in aluminium and gold based LDMOS RF power applications

In this paper we will compare the electromigration and hot carrier properties of the old (gold based) and new (aluminium based) metallisation schemes as used in RF base station power amplifiers manufactured by Philips Semiconductors. We will show that the latest generation shows excellent reliability performance while the RF performance has been strongly enhanced. This has been obtained by optimizing the process and device architecture. Both results of electromigration measurements on test structures and electromigration degradation of full devices will be shown. It is concluded that the latest generation LDMOS RF amplifiers shows excellent RF and reliability performance while using an aluminium based metallisation scheme.     

Typical failures in pyrolysis coils for ethylene cracking

This paper points out the main failure mechanisms for tubes and outlet parts of pyrolysis furnace coils. In most cases there is a combination of factors which ultimately lead to the failure, e. g. carburization and creep ductility exhaustion. This results in bulging, bending and ovalisation of the tubes. Also, brittle fracture during furnace trips can result in large, longitudinal cracks on many tubes in the furnace. The metallurgical background of the combined action of carburization and creep ductility exhaustion will be explained. Dense and stable oxide scales on the bore surface lower the amount of catalytic coke and also the carbon ingress into the alloy matrix (carburization). Carburization is also determined by the nickel content of the matrix. Creep ductility exhaustion is determined by the number of cycles (start/stop‐ and decoke cycles) and the nature (or severity) of these cycles. Pyrolysis tube failures can be prevented by a combination of proper furnace operation, materials choice, regular inspections and good design.     

Discriminative stimulus properties of mCPP: evidence for a 5-HT2C receptor mode of action

Phosphatidylinositol (PI) 3-kinase is known as one of the key molecules involved in the various biological events such as vesicle trafficking, cytoskeletal rearrangements and cell survival. T clarify the molecular basis underlying these events, we have tried to identify the proteins that can interact with phosphatidylinositol 3,4,5-trisphosphate (PIP3), the lipid product of PI3-kinase. Using a new PIP3 analogue, PIP3-APB, we synthesized an affinity column for PIP3 binding proteins. This enabled us to purify and identify several PIP3 binding proteins such as Tec tyrosine kinase, Gap1m, and Akt, as the candidates for the downstream molecules of PI3-kinase. All of these proteins contain PH domains, possible binding sites for phospholipids. Studies with various deletion mutants of Tec or Gap1m revealed that their PH domains are indeed the binding sites for PIP3. These results demonstrate that this PIP3-analogue binds various PIP3 binding proteins with high specificity and may be useful to elucidate the downstream mechanisms of PI3-kinases-mediated signaling pathways.     

Applications drive secure lightpath creation across heterogeneous domains

We realize an open, programmable paradigm for application-driven network control by way of a novel network plane - the "service plane" - layered above legacy networks. The service plane bridges domains, establishes trust, and exposes control to credited users/applications while preventing unauthorized access and resource theft. The authentication, authorization, and accounting subsystem and the dynamic resource allocation controller are the two defining building blocks of our service plane. In concert, they act upon an interconnection request or a restoration request according to application requirements, security credentials, and domain-resident policy. We have experimented with such service plane in an optical, large-scale testbed featuring two hubs (NetherLight in Amsterdam, StarLight in Chicago) and attached network clouds, each representing an independent domain. The dynamic interconnection of the heterogeneous domains occurred at Layer 1. The interconnections ultimately resulted in an optical end-to-end path (lightpath) for use by the requesting grid application.     

Stacked organic solar cells based on pentacene and

In order to improve photon harvesting, two small molecule organic solar cells are placed in series on top of each other. These stacked cells need an efficient recombination center in between both cells. In this study we test vacuum deposited metal layers as recombination centers with pentacene and buckminsterfullerene (C₆₀) as donor and acceptor, respectively. S-shaped curves are visible in the I–V characteristics when using thin layers of aluminum, indicating a barrier for extraction inside the device. Thin metal layers of gold or silver result in an increased open-circuit voltage without the appearance of these S-shaped features.     

On the Role of Bathocuproine in Organic Photovoltaic Cells

The effect of bathocuproine (BCP) on the optical and electrical properties of organic planar heterojunction photovoltaic cells is quantified by current–voltage characterization under 1 sun AM 1.5D simulated solar illumination and spectral response at short‐circuit conditions. By inserting a 10 nm BCP layer in an indium tin oxide (ITO)/subphthalocyanine (SubPc)/buckminsterfullerene (C₆₀)/BCP/Al thin‐film structure, an increase in power‐conversion efficiency from 0.05 to 3.0% is observed, mostly reflected in the enhanced open‐circuit voltage up to 920 mV. Furthermore, the incorporation of a 10‐nm BCP layer in an ITO/C₆₀/BCP/Al structure leads to an increase in built‐in potential from 250 to 850 mV, as demonstrated by electroabsorption. It is argued that BCP passivates C₆₀ such that a 10‐nm layer provides a sufficient buffer layer that prohibits Al contacting the C₆₀ where it would otherwise create donor states.     

Electro‐Optical Study of Subphthalocyanine in a Bilayer Organic Solar Cell

Ultra‐thin films of subphthalocyanine (SubPc) were grown onto Si/SiO₂ substrates by organic molecular beam deposition and the complex refractive index has been characterized by spectroscopic ellipsometry. The peak maximum in the extinction coefficient is determined to be 1.6 at 590 nm and the dielectric constant equals 3.9 in the limit of long wavelength. These values are extraordinary high when compared to the well‐known metal‐phthalocyanines and will be beneficial for the performance in a photovoltaic cell. The amorphous SubPc structure on top of indium‐tin‐oxide (ITO) as well as quartz glass is imaged by atomic force microscopy and scanning electron microscopy and we have characterized the nearly flat surface topology. Next, subphthalocyanine films in combination with buckminsterfullerene (C₆₀) have been studied in a planar bilayer donor/acceptor heterojunction by current density‐voltage characterization under AM 1.5 simulated illumination at various light intensities. A power conversion efficiency of 3.0 % under 1 sun was measured. Finally, the external and internal quantum efficiencies demonstrated peak maxima at 590 nm of 46 % and 55 %, respectively. Considering the abrupt junction at the donor/acceptor interface, the electron transfer from SubPc to the acceptor material is thus determined to be highly efficient.     

Self-triggered linear quadratic control

Self-triggered control is a recently proposed paradigm that abandons the more traditional periodic time-triggered execution of control tasks with the objective of reducing the utilization of communication resources, while still guaranteeing desirable closed-loop behavior. In this paper, we introduce a self-triggered strategy based on performance levels described by a quadratic discounted cost. The classical LQR problem can be recovered as an important special case of the proposed self-triggered strategy. The self-triggered strategy proposed in this paper possesses three important features. Firstly, the control laws and triggering mechanisms are synthesized so that a priori chosen performance levels are guaranteed by design. Secondly, they realize significant reductions in the usage of communication resources. Thirdly, we address the co-design problem of jointly designing the feedback law and the triggering condition. By means of a numerical example, we show the effectiveness of the presented strategy. In particular, for the self-triggered LQR strategy, we show quantitatively that the proposed scheme can outperform conventional periodic time-triggered solutions.     

Perfluorinated Subphthalocyanine as a New Acceptor Material in a Small‐Molecule Bilayer Organic Solar Cell

The complex refractive index of fluorinated subphthalocyanines (SubPcs) deposited by vacuum sublimation is determined by spectral ellipsometry. Their performance as acceptor material is characterized in a range of donor/acceptor heterojunctions in organic photovoltaic cells (OPVCs) by current–voltage measurements under 1 sun AM 1.5D simulated solar illumination and spectral response. Both electron and hole transfer between donor and acceptor materials is demonstrated. Power conversion efficiencies of 0.96% are found with an open‐circuit bias of 940 mV. Hence, it is shown that fluorinated SubPcs can be considered as an acceptor material in OPVCs with an absorption in the visible comparable to that of well‐known metallophthalocyanines.