The structure of K- and Cs-monolayers on Cu(0 0 1): diffraction experiments far from the Bragg point

The intensity analysis along the crystal truncation rods has been used to analyse in situ the adsorption behaviour and the structure of K and Cs on Cu(0 0 1) at submonolayer coverages and room temperature. Up to about 0.25 ML K atoms adsorb in hollow sites followed by formation of a quasihexagonal superstructure. In contrast, for Cs adsorption the data can be interpreted by the formation of quasihexagonal Cs islands that grow with increasing coverage. For K an effective radius of 1.6(1) Å independent of coverage is determined. For Cs we fnd d = 2.1 (1) Å after formation of the quasihexagonal superstructure

Resolution correction for surface X-ray diffraction at high beam exit angles

Owing to the two-dimensional periodicity of a superstructure on the crystal surface, the intensity in reciprocal space is continuously distributed along rods normal to the sample surface. The analysis of rod scans in surface X-ray diffraction provides information about the structure parameters normal to the sample surface. For high resolution to be achieved, the measurements must extend to momentum transfers q that are as large as possible. At large exit angles, the conventional Lorentz factor must be modified to take account of the finite aperture of the detector and the continuous intensity along the lattice rod. For two types of Z-axis diffractometer used in surface X-ray crystallography, an analytical expression for the resolution correction of rod-scan intensity data has been developed. It takes into account an anisotropic detector resolution T(, ), the finite width of the diffracted beam and the primary-beam divergence parallel to the sample surface, . The calculation of the convolution functions is simplified by a projection onto the q = 0 plane. The effects of different detector settings and the influences of the primary-beam divergence and the sample quality on the measured intensity are demonstrated for several examples

The atomic structure of ultrathin oxide films and interfaces studied by surface X-ray diffraction

X-ray diffraction (XRD) studies of the atomic structure of ultrathin oxide films and interfaces are presented, which are conducted within the framework of the Sonderforschungsbereich 762 (functionality of oxide interfaces). Knowledge of the atomic structure is at the heart of the study of functional oxides. XRD allows the investigation of complex systems frequently encountered in oxide systems (large unit cells, complex relaxation patterns, and structural and chemical disorder). Results are combined with first-principles calculations and complementary techniques providing a thorough understanding of the oxides' functionality. The structure analysis of the approximant (AP) to the 2D oxidic quasicrystal (QC) based on BaTiO3 (BTO) is discussed, the first oxide-type QC discovered. This AP is related to the Kepler tiling described 400 years ago. The LaFeO3/SrTiO3 interface is examined, which is a prototype for the formation of a 2D electron gas (2DEG). Subtle interfacial chemical roughness in combination with oxygen off-stoichiometry strongly influences the critical LaFeO3 thickness for the 2DEG formation. Finally, the analysis of the multiferroic BTO/ME(001) (ME = Fe, Pd, Pt) interface reveals that a submonolayer of impurities is the origin for the inversion of the BTO film/vacuum termination from BaO on Fe(001) to TiO2 on Pt(001)

X-ray structure analysis of the InSb ( )-(3 × 3) reconstruction

The (3 × 3) reconstruction of the InSb( ) surface has been analysed using grazing incidence X-ray diffraction. The reconstruction is characterized by hexamers above a complete InSb double-layer centred around an Sb atom. No vacancies are found in the structure as predicted theoretically. The results agree with scanning tunnelling microscopy measurements

Reviewing the current state of virtual reality integration in medical education : a scoping review protocol

Background Due to an increasing focus of medical curricula on clinical decision-making skills, new learning tools are constantly developed. Virtual reality (VR) is one of the emerging technologies with the potential to improve health professionals’ education. Highly realistic learning experiences with repeatable training scenarios can be created within a protected environment that is independent from real patients’ presence. Our project “medical tr.AI.ning” is following this approach aiming to simulate immersive virtual frst-person scenarios with intelligent, interactable virtual patients. So far, VR has been mainly used in surgical training, but there is evidence for efectiveness in training diferent procedural skills, such as cardiopulmonary resuscitation, knowledge acquisition, and improvement of reasoning and creativity, while still being cost-efective. The objective of this scoping review is to explore the usage and identify key areas of VR applications in the feld of medical education. Furthermore, the corresponding requirements, evaluation methods and outcomes, advantages, and disadvantages will be covered. Methods This scoping review protocol implements the updated JBI Scoping Review Methodology. In March 2022, a preliminary literature research in PubMed was performed by two independent reviewers to refne search terms and strategy as well as inclusion criteria of the protocol, accounting for actuality and scientifc relevance. The fnal search will be conducted using PubMed, ScienceDirect, Cochrane Library, Web of Science Core Collection, and JBI Evidence Synthesis. Search, study screening, and data extraction will be done in parallel and independently by two reviewers. Discrepancies will be handled by consensus or consulting a third review author. Discussion With this scoping review, we anticipate collating the range of application of VR in medical education while using a transparent and reproducible search strategy. This may contribute to the design and development of novel educational VR platforms and their integration into medical curricula while pointing out previous omissions and pitfalls

The Empirics of Economic Growth Over Time and Across Nations: A Unified Growth Perspective

This research develops an expanded unified growth theory that incorporates the endogenous accumulation of physical capital, population, human capital, and technology. The model incorporates a complementarity between physical capital and human capital and can be extended to a multi-country setting with international technology diffusion. The analytical characterization of the mechanisms behind the observed patterns of long-run growth and comparative development delivers a consistent explanation for a large set of seemingly unrelated empirical facts. A quantitative multi-country version of the model matches various empirical regularities of long-run growth dynamics and comparative development patterns that have previously been studied in isolation. The findings also shed new light on the role of the demographic transition for convergence patterns, the specification of cross-country growth regressions, technology spillovers, and the secular stagnation debate