Sputter deposition of porous thin films from metal/NaCl powder targets

A method to deposit porous thin films is elucidated. For this purpose, NaCl powder was mixed with a metal powder, cold pressed, and used as a target material in order to deposit a metal/NaCl thin film by DC magnetron sputtering. The thin film was immersed in water after deposition to remove the salt and to obtain a porous film. The low thermal conductivity of the target results in target heating and salt sublimation. In this way, the salt content in the layer and hence the film porosity are controlled by the discharge power. This procedure was carried out for Cu and Ti. The study focuses on the deposition of porous Cu thin films. From scanning transmission electron microscopy images, two film structures were observed. Films with a density higher than approximate to 40% of the bulk density exhibit a homogeneous spongelike microstructure with pores around 20nm. At lower density, a noncontinuous, fractured layer is formed. The blocks between the observed cracks manifest itself in the form of columnar pores. The lowest measured density was approximate to 23% of the bulk density. This approach combines the flexibility of powder targets and the scalability of magnetron sputtering and avoids the usage of aggressive chemicals

Impurity dominated thin film growth

Magnetron sputter deposition was applied to grow thin metal films in the presence of impurities. These impurities are ambient gas molecules and/or atoms from the residual gas present in the vacuum chamber. Seven materials were investigated: four single element metals (Al, Ag, Cu, and Cr), two widely applied alloys (Cu55Ni45 and Ni90Cr10), and one high entropy alloy (CoCrCuFeNi). The thin films were analyzed using X-ray diffraction to determine the domain size, the film texture, and the lattice parameter. The same trend for all studied materials is observed. When the ratio between the impurity and metal flux towards the substrate is low, the domain size is not affected by the presence of the impurities. In this regime, the incorporation of the impurities affects the lattice parameter. At high flux ratios, the change of the domain size can be described by a power law with the exponent equal to -1/2 for all studied materials. A kinetic Monte Carlo code is used to demonstrate this observed trend

The effect of the interval-between-sessions on prefrontal transcranial direct current stimulation (tDCS) on cognitive outcomes: a systematic review and meta-analysis

Recently, there has been wide interest in the effects of transcranial direct current stimulation (tDCS) of the dorsolateral prefrontal cortex (DLPFC) on cognitive functioning. However, many methodological questions remain unanswered. One of them is whether the time interval between active and sham-controlled stimulation sessions, i.e. the interval between sessions (IBS), influences DLPFC tDCS effects on cognitive functioning. Therefore, a systematic review and meta-analysis was performed of experimental studies published in PubMed, Science Direct, and other databases from the first data available to February 2016. Single session sham-controlled within-subject studies reporting the effects of tDCS of the DLPFC on cognitive functioning in healthy controls and neuropsychiatric patients were included. Cognitive tasks were categorized in tasks assessing memory, attention, and executive functioning. Evaluation of 188 trials showed that anodal vs. sham tDCS significantly decreased response times and increased accuracy, and specifically for the executive functioning tasks, in a sample of healthy participants and neuropsychiatric patients (although a slightly different pattern of improvement was found in analyses for both samples separately). The effects of cathodal vs. sham tDCS (45 trials), on the other hand, were not significant. IBS ranged from less than 1 h to up to 1 week (i.e. cathodal tDCS) or 2 weeks (i.e. anodal tDCS). This IBS length had no influence on the estimated effect size when performing a meta-regression of IBS on reaction time and accuracy outcomes in all three cognitive categories, both for anodal and cathodal stimulation. Practical recommendations and limitations of the study are further discussed

Hidden violence is a silent rape: prevention of sexual & gender-based violence against refugees & asylum seekers in Europe: a participatory approach report

From the arrival on European territory onwards, young female and male refugees, asylum seekers and undocumented migrants are extremely vulnerable to several types of gender-based violence. This results from the "Hidden Violence is a Silent Rape" Study. This book describes extensively all phases and actions in the project undertaken. We introduce the project, its aims, methods and beneficiaries in Chapter 1 with an overview of the different actions. In Chapter 2 , the results of the Community Based Participatory Research are reported. Chapter 3 and 4 reflect the proceedings and recommendations fo the Hidden Violence is a Silent Rape Seminar

Generative inverse design of multimodal resonant structures for locally resonant metamaterials

In the development of locally resonant metamaterials, the physical resonator design is often omitted and replaced by an idealized mass-spring system. This paper presents a novel approach for designing multimodal resonant structures, which give rise to multi-bandgap metamaterials with predefined band gaps. Our method uses a conditional variational autoencoder to identify nontrivial patterns between design variables of complex-shaped resonators and their modal effective parameters. After training, the cost of generating designs satisfying arbitrary criteria - frequency and mass of multiple modes - becomes negligible. An example of a resonator family with six geometric variables and two targeted modes is further elaborated. We find that the autoencoder performs well even when trained with a limited dataset, resulting from a few hundred numerical modal analyses. The method generates several designs that very closely approximate the desired modal characteristics. The accuracy of the best designs, proposed by the auto-encoder, is confirmed in tests of 3D-printed resonator prototypes. Further experiments demonstrate the close agreement between the measured and desired dispersion relation of a sample metamaterial beam

Modeling reactive magnetron sputtering : opportunities and challenges

The complexity of the reactive magnetron sputtering process is demonstrated by four simulation examples. The examples, commonly encountered during the application of this process for thin film deposition, are described by a numerical model for reactive sputter deposition. A short description of the current model precedes these case studies. In the first example, redeposition of sputtered atoms on the target is studied by its effect on the hysteresis behavior often observed during reactive sputtering. Secondly, the complexity of current-voltage characteristics during reactive magnetron sputtering is treated. The influence of substrate rotation and the pulsing of the discharge current illustrate the time dependence of the reactive sputtering process. As a conclusion, the two main challenges for a further improvement of the model are discussed

Sexual and Reproductive Health and Rights of Refugees, Asylum Seekers & Undocumented Migrants

In 2006 the European Refugee Fund undertook a call for proposals, which resulted in the project presented in this report. The 18-month project started on 1 August 2007 and ran until 31 January 2009. The general aim of the project was to improve the SRH of refugees and asylum seekers in the EU, by setting up a network for the promotion of the SRH&R of refugees and asylum seekers in Europe and beyond

Transcranial direct current stimulation (tDCS) modulation of picture naming and word reading:A meta-analysis of single session tDCS applied to healthy participants

Recent reviews quantifying the effects of single sessions of transcranial direct current stimulation (or tDCS) in healthy volunteers find only minor effects on cognition despite the popularity of this technique. Here, we wanted to quantify the effects of tDCS on language production tasks that measure word reading and picture naming. We reviewed 14 papers measuring tDCS effects across a total of 96 conditions to a) quantify effects of conventional stimulation on language regions (i.e., left hemisphere anodal tDCS administered to temporal/frontal areas) under normal conditions or under conditions of cognitive (semantic) interference; b) identify parameters which may moderate the size of the tDCS effect within conventional stimulation protocols (e.g., online vs offline, high vs. low current densities, and short vs. long durations), as well as within types of stimulation not typically explored by previous reviews (i.e., right hemisphere anodal tDCS or left/right hemisphere cathodal tDCS). In all analyses there was no significant effect of tDCS, but we did find a small but significant effect of time and duration of stimulation with stronger effects for offline stimulation and for shorter durations (< 15 min). We also found some indication of publication bias towards reporting positive effects. We encourage further experimentation in order resolve the disparity between the current popularity of tDCS and its poor efficacy in healthy participants

How to characterize the function of a brain region

Many brain regions have been defined, but a comprehensive formalization of each region’s function in relation to human behavior is still lacking. Current knowledge comes from various fields, which have diverse conceptions of ‘functions’. We briefly review these fields and outline how the heterogeneity of associations could be harnessed to disclose the computational function of any region. Aggregating activation data from neuroimaging studies allows us to characterize the functional engagement of a region across a range of experimental conditions. Furthermore, large-sample data can disclose covariation between brain region features and ecological behavioral phenotyping. Combining these two approaches opens a new perspective to determine the behavioral associations of a brain region, and hence its function and broader role within large-scale functional networks