ViPER: simulation software for high aspect ratio plasma etching of silicon

The process of pattern transfer of desired topological integrated circuits features into silicon or other semiconductor compounds plays a critical role for the production of microelectronic and photonic devices, and micro- and nanoelectromechanical systems. Any deviation from the desired shape of the pattern limits density, yield, and reliability of these devices. Gas reactivity, pressure, ion, electron, and reactant transport to the surface, and product transport away from the surface, have been identified as important issues that control the microscopic uniformity in high aspect ratio etching. A plasma etching simulation software, containing corresponding physical models, can be used to establish a link between etch process parameters such as pressure, rf power, etching gas chemistry, temperature, and the physical and chemical process parameters like energy and angular distribution of ions and neutrals, radical sticking, and surface charging. ViPER (Virtual Plasma Etch Reactor) is a full featured plasma processing simulation software developed at Ilmenau University of Technology, Department of Microelectronic and Nanoelectronic Systems (MNES) [http://www.tu-ilmenau.de/en/mne-mns/research/plasma-etching/viper-download]. The simulator allows a deep analysis of the most significant effects like reactive ion etching lag, charging, notching, bowing, faceting, microtrenching, profile shape dependence, and gives more insight into the physical phenomena occurring in the plasma reactor during plasma etching process, helping engineers to understand how plasma etching works.     

On the Substrate Binding of Linoleate 9-Lipoxygenases

Lipoxygenases (LOX; linoleate:oxygen oxidoreductase EC 1.13.11.12) consist of a class of enzymes that catalyze the regio- and stereo specific dioxygenation of polyunsaturated fatty acids. Here we characterize two proteins that belong to the less studied class of 9-LOXs, Solanum tuberosum StLOX1 and Arabidopsis thaliana AtLOX1. The proteins were recombinantly expressed in E. coli and the product specificity of the enzymes was tested against different fatty acid substrates. Both enzymes showed high specificity against all tested C18 fatty acids and produced (9S)-hydroperoxides. However, incubation of the C20 fatty acid arachidonic acid with AtLOX1 gave a mixture of racemic hydroperoxides. On the other hand, with StLOX1 we observed the formation of a mixture of products among which the (5S)-hydroperoxy eicosatetraenoic acid (5S-H(P)ETE) was the most abundant. Esterified fatty acids were no substrates. We used site directed mutagenesis to modify a conserved valine residue in the active site of StLOX1 and examine the importance of space within the active site, which has been shown to play a role in determining the positional specificity. The Val576Phe mutant still catalyzed the formation of (9S)-hydroperoxides with C18 fatty acids, while it exhibited altered specificity against arachidonic acid and produced mainly (11S)-H(P)ETE. These data confirm the model that in case of linoleate 9-LOX binding of the substrate takes place with the carboxyl-group first. Sequence data: The nucleotide sequences reported in this paper are annotated in the GenBank/EMBL data bank under the accession numbers Q06327 and S73865.     

A polyamidoamine dendrimer as a selective colorimetric and ratiometric fluorescent sensor for Li+ cations in alkali media

In a DMF + NaOH medium, a polyamidoamine dendrimer having sixteen 1,8-naphthalimide fragments in its periphery, formed a complex only with Li⁺ ions, detected by a colour change from red to yellow and by a significant increase in fluorescence intensity. The dendrimer can be used as a selective sensor for Li⁺ ions in the presence of other alkali ions such as Na⁺ or K⁺.     

The optical viscometer based on the vibrating fiber partially submerged in fluid

The vibrating fiber partially submerged in fluid has been shown to be an effective device for the viscosity sensing. In this study, small vibrational amplitude of the fiber (<1.0 μm) is detected by the optical method utilizing a forward light scattering pattern. An analytical solution of the partially submerged fiber vibration with damping has been found and results agree well with experimental data in the wide ranges of the different liquids and depths. It has been shown that variations of the maximum vibrational amplitude (MVA) and the bandwidth depend linearly on (ρ_lμ_l)^1/2 and split over the liquid depth. Based on the results a simple way for the viscosity extraction from both the MVA and the bandwidth has been suggested and an explicit formula for the achievable accuracy of the viscosity sensing has been derived. Experiments have confirmed the method of the viscosity extraction.     

Automatic Parallelization: Executing Sequential Programs on a Task-Based Parallel Runtime

There are billions of lines of sequential code inside nowadays’ software which do not benefit from the parallelism available in modern multicore architectures. Automatically parallelizing sequential code, to promote an efficient use of the available parallelism, has been a research goal for some time now. This work proposes a new approach for achieving such goal. We created a new parallelizing compiler that analyses the read and write instructions, and control-flow modifications in programs to identify a set of dependencies between the instructions in the program. Afterwards, the compiler, based on the generated dependencies graph, rewrites and organizes the program in a task-oriented structure. Parallel tasks are composed by instructions that cannot be executed in parallel. A work-stealing-based parallel runtime is responsible for scheduling and managing the granularity of the generated tasks. Furthermore, a compile-time granularity control mechanism also avoids creating unnecessary data-structures. This work focuses on the Java language, but the techniques are general enough to be applied to other programming languages. We have evaluated our approach on 8 benchmark programs against OoOJava, achieving higher speedups. In some cases, values were close to those of a manual parallelization. The resulting parallel code also has the advantage of being readable and easily configured to improve further its performance manually.     

Disclosing the Biocide Activity of α-Ag2−2xCuxWO4 (0 ≤ x ≤ 0.16) Solid Solutions

In this work, α-Ag_2−2xCu_xWO₄ (0 ≤ x ≤ 0.16) solid solutions with enhanced antibacterial (against methicillin-resistant Staphylococcus aureus) and antifungal (against Candida albicans) activities are reported. A plethora of techniques (X-ray diffraction with Rietveld refinements, inductively coupled plasma atomic emission spectrometry, micro-Raman spectroscopy, attenuated total reflectance–Fourier transform infrared spectroscopy, field emission scanning electron microscopy, ultraviolet–visible spectroscopy, photoluminescence emissions, and X-ray photoelectron spectroscopy) were employed to characterize the as-synthetized samples and determine the local coordination geometry of Cu²⁺ cations at the orthorhombic lattice. To find a correlation between morphology and biocide activity, the experimental results were sustained by first-principles calculations at the density functional theory level to decipher the cluster coordinations and electronic properties of the exposed surfaces. Based on the analysis of the under-coordinated Ag and Cu clusters at the (010) and (101) exposed surfaces, we propose a mechanism to explain the biocide activity of these solid solutions.     

A new analytical model for the CQ switch throughput calculation under the bursty traffic

In this paper we propose a new analytical iterative method for the throughput calculation of the Crosspoint Queued (CQ) switch with a random scheduling algorithm under the bursty traffic model. This method is verified by comparing it with the simulation results, which shows a very good match. To the authors’ knowledge, this is the first analytical method for the throughput calculation of such a switch for the bursty traffic model.