Self-organized pore formation and open-loop-control in semiconductor etching

Electrochemical etching of semiconductors, apart from many technical applications, provides an interesting experimental setup for self-organized structure formation capable e.g. of regular, diameter-modulated, and branching pores. The underlying dynamical processes governing current transfer and structure formation are described by the Current-Burst-Model: all dissolution processes are assumed to occur inhomogeneously in time and space as a Current Burst (CB); the properties and interactions between CB's are described by a number of material- and chemistry- dependent ingredients, like passivation and aging of surfaces in different crystallographic orientations, giving a qualitative understanding of resulting pore morphologies. These morphologies cannot be influenced only by the current, by chemical, material and other etching conditions, but also by an open-loop control, triggering the time scale given by the oxide dissolution time. With this method, under conditions where only branching pores occur, the additional signal hinders side pore formation resulting in regular pores with modulated diameter

Toward an Instrumented Strength Microprobe – Origins of the Oliver-Pharr Method and Continued Advancements in Nanoindentation: Part 1

Sub-micron instrumented indentation testing and standardized nanoindentation testing systems have become commonplace within the materials engineering community. Though commonly utilized for mechanical characterization, general appreciation and understanding of the governing theory, formulations and best practices underpinning modern nanoindentation systems appears to remain relatively elusive to the general materials science and engineering community as well as nanoindentation practitioners using such systems for mechanical assessment. Accordingly, the present chapter details how nanoindentation methods emerged and how the Oliver-Pharr method of nanoindentation testing and analysis was constructed and refined to yield theoretically consistent and readily implementable attributes for probing small-scale mechanical properties via microscopy free indentation testing

Effects of Structure and Morphology of Hydrothermally Grown ZnO Particles on the Photovoltaic Performance of Dye Sensitized Solar Cell

Highly ordered microporous ZnO materials with crystalline structure were synthesized hydrothermally from three different Zn-precursorsnamely: Zinc-acetate, chloride, and nitrate. XRD investigations revealed that all the obtained powders have single phase zincite structure. The powder morphology was investigated by SEM which showed that the starting Zn-precursor affects the shape as well as the size of the obtained particles. A photoelectrodes fabricated using the three different synthesized microporous ZnO particles showed variation in photocurrent density (Jsc) dye loading and hence the efficiency with variation in structure texture, morphology and particle size. DSSC built with photoelectrodes made from Zn-acetate has the highest efficiency (5.4%) which is attributed to having lowest particle size and largest surface area available for dye loading. This increases light harvesting at the photoelectrode which in turn increases short circuit current density. On the other hand, the lowest current density (5.65mA/cm2) is obtained for DSSC with photolelctrodes made from Zn-nitrate

Antibiotic free selection for the high level biosynthesis of a silk-elastin-like protein

Silk-elastin-like proteins (SELPs) are a family of genetically engineered recombinant protein polymers exhibiting mechanical and biological properties suited for a wide range of applications in the biomedicine and materials fields. They are being explored as the next generation of biomaterials but low productivities and use of antibiotics during production undermine their economic viability and safety. We have developed an industrially relevant, scalable, fed-batch process for the high level production of a novel SELP in E. coli in which the commonly used antibiotic selection marker of the expression vector is exchanged for a post segregational suicide system, the separate-component-stabilisation system (SCS). SCS significantly augments SELP productivity but also enhances the product safety profile and reduces process costs by eliminating the use of antibiotics. Plasmid content increased following induction but no significant differences in plasmid levels were discerned when using SCS or the antibiotic selection markers under the controlled fed-batch conditions employed. It is suggested that the absence of competing plasmid-free cells improves host cell viability and enables increased productivity with SCS. With the process developed, 12.8 g L(-1) purified SELP was obtained, this is the highest SELP productivity reported to date and clearly demonstrates the commercial viability of these promising polymers.This work was financed by the European Commission via the 7th Framework Programme Project EcoPlast (FP7-NMP-2009-SME-3), by national funds from the FCT through EXPL/BBB-BIO/1772/2013-FCOMP-010124-FEDER-041595, the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569) and a fellowship to SRC (SFRH/BPD/89980/2012), as well as from ERDF through COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI). T.C. is supported by the FCT, the European Social Fund, the Programa Operacional Potencial Humano and the Investigador FCT Programme (IF/01635/2014). All the technical staff at the CBMA are thanked for their skilful technical assistance.info:eu-repo/semantics/publishedVersio

Excellence Mapping: Bibliometric study of the productivity and the impact of scientific publications of the JRC: Mapping of scientific areas and application areas: Volume 2: Analysis of the JRC collaborations with world academic institutions

The present report is the second volume of the Joint Research Centre (JRC) excellence mapping. While the first volume concentrates on the productivity and the impact of the JRC scientific work, in terms of publications and citations, in general, the present volume analyses a particular subset of publications that have been jointly produced with scientists from other organisations. In particular, it analyses the co-authored publications between the JRC and the world academic institutions, which are highly ranked in different world university rankings. In the context of this analysis, three different rankings have been used (Times higher education ranking, QS world university ranking and Academic ranking of world universities) and the Top-100 academic institutions in each of them have been analysed in order to investigate: 1) the existence of formal agreements with the JRC; 2) number of co-authored publications with the JRC and 3) the scientific areas where the collaborations occur.JRC.A.2-Planning, Evaluation and Knowledge Managemen