Accurate measurement of the steady-state swelling behavior of SU-8 negative photo resist

The swelling behaviour of SU-8 2000 series is investigated. This is done using on-wafer micro machined stress indicator structures. The indicator structures convert the stress in the material to a measurable displacement. When SU-8 is submersed into a solvent, the polymer matrix of the SU-8 can absorb some of the solvent molecules. As a result, the SU-8 can expand and the built in tensile stress is partially relieved. The swelling can thus be measured directly and independently of lithography parameters. For this study, the indicator structures are immersed in Propyle Glycol Methyl Ether Acetate (PGMEA), isopropyl alcohol (IPA) and water.     

A Mechanistically and Operationally Simple Route to Metal–N-Heterocyclic Carbene (NHC) Complexes

We have been puzzled by the involvement of weak organic and inorganic bases in the synthesis of metal–N-heterocyclic carbene (NHC) complexes. Such bases are insufficiently strong to permit the presumed required deprotonation of the azolium salt (the carbene precursor) prior to metal binding. Experimental and computational studies provide support for a base-assisted concerted process that does not require free NHC formation. The synthetic protocol was found applicable to a number of transition-metal- and main-group-centered NHC compounds and could become the synthetic route of choice to form M–NHC bonds.     

The photon-ion merged-beams experiment PIPE at PETRA III—The first five years

The Photon-Ion Spectrometer at PETRA III—in short, PIPE—is a permanently installed user facility at the \"Variable Polarization XUV Beamline\" P04 of the synchrotron light source PETRA III operated by DESY in Hamburg, Germany. The careful design of the PIPE ion-optics in combination with the record-high photon flux at P04 has lead to a breakthrough in experimental studies of photon interactions with ionized small quantum systems. This short review provides an overview over the published scientific results from photon-ion merged-beams experiments at PIPE that were obtained since the start of P04 operations in 2013. The topics covered comprise photoionization of ions of astrophysical relevance, quantitative studies of multi-electron processes upon inner-shell photoexcitation and photoionization of negative and positive atomic ions, precision spectroscopy of photoionization resonances, photoionization and photofragmentation of molecular ions, and of endohedral fullerene ions.     

Insights into the Reaction Mechanism of Ethanol Conversion into Hydrocarbons on H‐ZSM‐5

Ethanol dehydration to ethene is mechanistically decoupled from the production of higher hydrocarbons due to complete surface coverage by adsorbed ethanol and diethyl ether (DEE). The production of C₃₊ hydrocarbons was found to be unaffected by water present in the reaction mixture. Three routes for the production of C₃₊ hydrocarbons are identified: the dimerization of ethene to butene and two routes involving two different types of surface species categorized as aliphatic and aromatic. Evidence for the different types of species involved in the production of higher hydrocarbons is obtained via isotopic labeling, continuous flow and transient experiments complemented by UV/Vis characterization of the catalyst and ab initio microkinetic modeling.     

Direct and Indirect Bactericidal Effects of Cold Atmospheric-Pressure Microplasma and Plasma Jet

The direct and indirect bactericidal effects of dielectric barrier discharge (DBD) cold atmospheric-pressure microplasma in an air and plasma jet generated in an argon-oxygen gas mixture was investigated on Staphylococcus aureus and Cutibacterium acnes. An AC power supply was used to generate plasma at relatively low discharge voltages (0.9–2.4 kV) and frequency (27–30 kHz). Cultured bacteria were cultivated at a serial dilution of 10⁻⁵, then exposed to direct microplasma treatment and indirect treatment through plasma-activated water (PAW). The obtained results revealed that these methods of bacterial inactivation showed a 2 and 1 log reduction in the number of survived CFU/mL with direct treatment being the most effective means of treatment at just 3 min using air. UV–Vis spectroscopy confirmed that an increase in treatment time at 1.2% O₂, 98.8% Ar caused a decrease in O₂ concentration in the water as well as a decrease in absorbance of the peaks at 210 nm, which are attributed NO₂⁻ and NO₃⁻ concentration in the water, termed denitratification and denitritification in the treated water, respectively.     

Nano-scale chemical and structural segregation induced in surface layer of NaNbO3 crystals with thermal treatment at oxidising conditions studied by XPS,AFM, XRD,and electric properties tests

The process of ionic segregation in the surface layer induced by the thermal treatment of the NaNbO₃ crystal was studied. The study of the as grown crystal and the crystal heated at 970 K in ambient air was carried out for comparison. The changes in the concentration of the elements within the surface layer were determined using XPS measurements. The AFM technique was applied to determine the surface morphology related to nano-scale transformation. The possibility of appearance of the Ruddlesden–Popper phases was detected by the XRD test. The change in the features of the electric permittivity, the loss tangent, and the electric conductivity was ascribed to the marked participation of the chemically modified surface layer in the measured effective electrical properties.