Current Status and Future Challenges for Teacher Training for ESD

STEM micrographs of 99% ¹³C graphene imaged with electrons accelerated by a voltage of 100 kV. Each item in the fileset is a ZIP archive containing a single time series of consecutive frames recorded with a medium angle annular dark field detector until an ejection was observed

Phase offset method of ptychographic contrast reversal correction

The contrast transfer function of direct ptychography methods such as the single side band (SSB) method are single signed, yet these methods still sometimes exhibit contrast reversals, most often where the projected potentials are strong. In thicker samples central focusing often provides the best ptychographic contrast as this leads to defocus variations within the sample canceling out. However focusing away from the entrance surface is often undesirable as this degrades the annular dark field (ADF) signal. Here we discuss how phase wrap asymptotes in the frequency response of SSB ptychography give rise to contrast reversals, without the need for dynamical scattering, and how these can be counteracted by manipulating the phases such that the asymptotes are either shifted to higher frequencies or damped via amplitude modulation. This is what enables post collection defocus correction of contrast reversals. However, the phase offset method of counteracting contrast reversals we introduce here is generally found to be superior to post collection application of defocus, with greater reliability and generally stronger contrast. Importantly, the phase offset method also works for thin and thick samples where central focusing does not

Aligned Stacking of Nanopatterned 2D Materials for High-Resolution 3D Device Fabrication

Two-dimensional materials can be combined by placing individual layers on top of each other, so that they are bound only by their van der Waals interaction. The sequence of layers can be chosen arbitrarily, enabling an essentially atomic-level control of the material and thereby a wide choice of properties along one dimension. However, simultaneous control over the structure in the in-plane directions is so far still rather limited. Here, we combine spatially controlled modifications of 2D materials, using focused electron irradiation or electron beam induced etching, with the layer-by-layer assembly of van der Waals heterostructures. The presented assembly process makes it possible to structure each layer with an arbitrary pattern prior to the assembly into the heterostructure. Moreover, it enables a stacking of the layers with accurate lateral alignment, with an accuracy of currently 10 nm, under observation in an electron microscope. Together, this enables the fabrication of almost arbitrary 3D structures with highest spatial resolution

Aligned Stacking of Nanopatterned 2D Materials for High-Resolution 3D Device Fabrication

Two-dimensional materials can be combined by placing individual layers on top of each other, so that they are bound only by their van der Waals interaction. The sequence of layers can be chosen arbitrarily, enabling an essentially atomic-level control of the material and thereby a wide choice of properties along one dimension. However, simultaneous control over the structure in the in-plane directions is so far still rather limited. Here, we combine spatially controlled modifications of 2D materials, using focused electron irradiation or electron beam induced etching, with the layer-by-layer assembly of van der Waals heterostructures. The presented assembly process makes it possible to structure each layer with an arbitrary pattern prior to the assembly into the heterostructure. Moreover, it enables a stacking of the layers with accurate lateral alignment, with an accuracy of currently 10 nm, under observation in an electron microscope. Together, this enables the fabrication of almost arbitrary 3D structures with highest spatial resolution

12C graphene, 95 kV

STEM micrographs of 99% ¹²C graphene imaged with electrons accelerated by a voltage of 95 kV. Each item in the fileset is a ZIP archive containing a single time series of consecutive frames recorded with a medium angle annular dark field detector until an ejection was observed.<br

12C graphene, 85 kV

STEM micrographs of 99% ¹²C graphene imaged with electrons accelerated by a voltage of 85 kV. Each item in the fileset is a ZIP archive containing a single time series of consecutive frames recorded with a medium angle annular dark field detector until an ejection was observed.<br

12C graphene, 100 kV

STEM micrographs of 99% ¹²C graphene imaged with electrons accelerated by a voltage of 100 kV. Each item in the fileset is a ZIP archive containing a single time series of consecutive frames recorded with a medium angle annular dark field detector until an ejection was observed.<br

12C graphene, 90 kV

STEM micrographs of 99% ¹²C graphene imaged with electrons accelerated by a voltage of 90 kV. Each item in the fileset is a ZIP archive containing a single time series of consecutive frames recorded with a medium angle annular dark field detector until an ejection was observed.<br

13C graphene, 90 kV

STEM micrographs of 99% ¹³C graphene imaged with electrons accelerated by a voltage of 90 kV. Each item in the fileset is a ZIP archive containing a single time series of consecutive frames recorded with a medium angle annular dark field detector until an ejection was observed

Additional file 1: of Variation in haemodynamic monitoring for major surgery in European nations: secondary analysis of the EuSOS dataset

Supplemental digital content. Patient flow diagram (supplementary Figure 1), variation in the use of different types of cardiac output monitoring in European nations (supplementary Figure 2) and types of haemodynamic monitoring used in European nations (supplementary Table). (PDF 333 kb