Crystal structures and growth mechanism for ultrathin films of ionic compound materials: FeO(111) on Pt(111)

The growth and atomic structures of epitaxial iron-oxide films on Pt(111) were studied with scanning tunneling microscopy and high-resolution low-energy electron diffraction. During the initial layer-by-layer growth of FeO(111) four different structures are formed as the coverage increases to 2.5 monolayers, then a three-dimensional growth of Fe3O4(111) islands begins. The structural transformations demonstrate that the relaxations within the FeO(111) films and the Stranski-Krastanov growth mode are induced by electrostatic surface energies, which dominate the energetics of thin film systems made up of ionic compound materials

Thermal analysis - TDS

Basics 1. Idea, desorption, experimental, example 2. Coverage determination, site occupation and warnings 3. Desorption order Quantitative 4. Redhead analysis 5. Adsorbate-adsorbate interaction: the Elovich-equation 6. “Complete analysis” 7. “Leading edge analysis” 8. Conclusion

Auger electron spectroscopy (AES) and modulation techniques

Content: AES - basics AES - surface sensitivity Electron energy analysis Modulation method, Lock-In Qualitative/quantitative analysis Chemical information e beam influence

Atomic structure of Si and Ge surfaces: Models for (113), (115), and stepped (001) vicinal surfaces

A new class of structure models for the (113) and (115) orientations of Si and Ge is proposed. They are based on dimer and adatom formation as the main building blocks for the reduction of dangling bonds (DB), on relaxation towards more sp2- or s2p3-like configurations, and on the minimization of strain. Four structural alternatives are discussed for (113) which are consistent with the observed 3×1 and 3×2 periodicities. They have either a low DB density and large strain or a higher DB density and low strain. For Si(113), a decision between them on the basis of the available experimental results is not unique. The analysis of the orientation-dependent adsorption of H2S and NO in terms of preferential adsorption by certain structural elements favors the models for Ge(113) which have not the minimum DB density but the minimum of strain. Steps on (001) vicinals induce strain due to bond stretching which is equilibrated over the terraces as long as they are wide enough. The switching of the twofold periodicity of the dimers along [1¯10] on (001) and its vicinals to the threefold periodicity at (115) is explained to occur because the 3×n models resolve bond stretching into bond bending by a meandering arrangement of microterraces which are separated by the energetically most favorable type-SA single-layer steps

T- and p-Measurement

T-measuerement: Resistance T-detectors - Thermocouple - Pyrometer - comparison P-measurement: Direct: Mechanical force - Indirect: Heat conductivity - Indirect: Gas ionization - gauge combinations - QM

A matched case-control study to assess the association between non-steroidal anti-inflammatory drug use and thrombotic microangiopathy

Several case reports suggest that non-steroidal anti-inflammatory drugs (NSAIDs) may be associated with thrombotic microangiopathy (TMA). We conducted a matched case-control study with linked administrative healthcare data in Ontario, Canada to assess the relationship between TMA hospitalization and recent exposure to prescription NSAIDs versus acetaminophen (where the latter was a referent group with no known association with TMA). Cases and controls were drawn from a source population of adults who filled a prescription for NSAIDs or acetaminophen between 1996 and 2015 (restricted to adults with prescription drug benefits). Cases comprised individuals hospitalized with TMA between 1996 and 2015. Controls were matched to cases (4:1) on demographic and medical risk factors. Cases (n=38) were less likely to have received a recent prescription for NSAIDs relative to acetaminophen (adjusted odds ratio 0.37, 95% confidence interval 0.16-0.84). Results were similar in two additional analyses with alternative referent groups. Overall, the results of this study do not support a harmful association between NSAID use and TMA

Interiors

None provided

Surface science meets catalysis research: epitaxial iron oxide films for in-situ model catalysis

I will review a fairly successful attempt to bridge the gaps between surface science studies and real catalysis for the case of ethylbenzene (EB) dehydrogenation to styrene (St) over unpromoted and K-promoted iron oxide catalysts. Epitaxial films of Fe3O4(111), a-Fe2O3(0001), KxFe22O34 and KFeO2 were prepared and characterized using surface science methods. Their catalytic behavior was studied after vacuum-transfer in a micro flow reactor, followed by post-reaction surface analysis. The results are : (i) Defects are necessary for the dehydrogenation step; (ii) most active is Fe3+ in Fe2O3 or KFexOy; (iii) unpromoted catalysts deactivate by reduction to Fe3O4 and by coking; (iv) both can be prevented by some oxygen in the feed; (v) K is catalytically inactive but suppresses reduction and catalyses carbon removal; (vi) K2Fe22O34 and KFeO2 are K-reservoir phases; (vii) “steaming” (reaction in steam without EB) exhausts the K-reservoir phases; (viii) coke has non-zero catalytic activity and contributes to conversion in real catalysis. In cooperation with the ICVT in Stuttgart, microkinetic modelling was performed aiming at a prediction of the behaviour of technical catalysts. Using physically meaningful parameters, mostly determined in surface science experiments, an excellent fit was achieved which could even be extented to porous samples